23:00: Houghton and Sunderland South – First past the post
This new constituency was created out of the Labour strongholds of Houghton and Washington East and Sunderland South, and is likely to remain in the hands of Houghton's Fraser Kemp.
MP for Sunderland South Chris Mullin (pictured) stood down.
Sunderland South took great pride in being the first constituency to declare on election night, and is likely to pass that honour to its successor.
In 2005 the seat won the race for the fourth election in a row, declaring at 22.43.
00:01 Antrim North – A family affair
Ian Paisley Jnr is expected to hold the seat held by his father for 40 years, despite a challenge from the anti-Stormont party Traditional Unionist Voice. Ian Paisley Snr had a majority of 17,965 in 2005.
00:01 Lagan Valley – Another family affair
This seat was held by the UUP until 2004 when sitting MP Jeffrey Donaldson defected to the DUP. Former UUP leader David Trimble's wife Daphne is the UUP/Conservative candidate this time round, but Donaldson is expected to hold the seat.
00:45 Birmingham Edgbaston – Memories of 1997
Labour's victory here in 1997 was the symbol of the landslide that swept Tony Blair into power, with the newly elected MP Gisela Stuart securing Labour's first gain of the night.
Stewart is defending a 2,349 majority, and the seat has traditionally been a good indicator of the wider national trend.
01:00 Castle Point – Independence Day
Sitting MP Bob Spink was elected in 2005 as a Conservative, but defected to Ukip in 2008 and at the end of the last parliament was sitting as an Independent.
This is traditionally Conservative Party territory and Spink's ability to hold onto the seat may depend on how much personal goodwill he has managed to amass since he left the Tory party.
In the last Parliament Spink became famous for finding inventive ways to mention his constituency during Commons debates.
01:00 Basildon South and Thurrock East – The bellweather seat
This is a key win for the Tories and it could provide the first ministerial scalp of the night – Angela E Smith, minister of state at the cabinet office, is contesting the newly-drawn Basildon seat – the bookies predict she will lose to Conservative candidate Stephen Metcalfe.
Basildon swung to New Labour in 1997 and is seen as a classic bellweather seat.
01:00 Batttersea – Linton's last stand
New Labour won Battersea in 1997, and former journalist Martin Linton only just held on in 2005 with a majority of 163. Expect to see the Tory candidate, Jane Ellison, win by considerably more than that.
01:00 Leeds North East – Northern glory
The Tories are expected to gain this Leeds seat that they lost in 1997 to Labour's Fabian Hamilton, along with the neighbouring seat of Elmet and Rothwell.
If the Tories are going to win, northern urban seats like these are vital.
01:00 Blackburn – Straw man
A city with a sizeable Muslim population, Labour feared the then-foreign secretary Jack Straw would lose his seat in 2005 in the wake of the Iraq war.
But while his share of the vote dropped 12 per cent he held on with a majority of 8, 009.
Now justice secretary, Straw is hoping to escape a Tory surge in the north and has been largely absent from Labour's national campaign.
01:00 Tooting – Khan he do it?
The Tories have poured resources into this south London seat and are confident they can unseat transport minister Sadiq Khan, whose majority in 2005 was 5,381.
If they succeed, it would mean two ministerial scalps this early in the night, which is bound to cheer the Tory troops.
01:00 Telford - the Wright stuff
Tory candidate Tom Biggins looks set to take this Shropshire seat from government whip David Wright.
Wright was an early Twitter victim, when he claimed comments on his feed about Tory "scum-sucking pigs" were the work of a hacker.
01:30 Pendle – A Rolls Royce seat
Home to a major Rolls Royce factory, Pendle looks likely to fall to the Tories, a defeat for former MP Gordon Prentice.
This seat, Tory until 1992, is an example of where Cameron must make inroads if he is to come close to winning a majority.
01:30 South Shields – Anointing the Dauphin
Foreign secretary David Miliband is expected to romp home in his Tyneside constituency.
It will be too early for him to talk about defeat in his victory speech, but all eyes will be on the young pretender if, as expected, Labour crash to defeat.
02:00 Eastleigh – Huhne's war at home
With Liberal Democrat home affairs spokesman Chris Huhne holding a majority of just 568, the Conservatives would have initially seen the Hampshire seat as a shoo-in for their candidate Maria Hutchings.
But Huhne has realistic hopes that a combination of his high profile and the Nick Clegg television debate poll bounce will be enough to hold off the Tory challenge.
02:00 Kirkcaldy & Cowdenbeath – Brown safe at last
The first of the party leaders to be returned to Parliament will be Gordon Brown. While his party may be headed for opposition the prime minister is in no danger of losing his own seat - in 2005 he won a whopping majority of 18,216 and 43 per cent of the vote.
02:00 Norwich South – Decapitation strategy (second time lucky)
In 2005 the then-home secretary Charles Clarke managed to see off the failed Liberal Democrat 'decapitation strategy'. While there was a 7 per cent swing to the Lib Dems, he held on with a majority of 3,653.
But he may be for the chop this time around, as the Gordon Brown critic contends with an apparent slump in Labour support nationally and an energised Liberal Democrat party.
02:00 Exeter – Student city
Culture secretary Ben Bradshaw defends his 7,665 vote majority in seat with a high student population, with about 6,000 registered.
The Tories fighting for the Exeter seat have accused the government of "neglecting" the South West.
Former BBC reporter Bradshaw said the constituency was a "success story", a seat which has historically been Conservative.
02:00 Dunfermline & Fife West – Rennie's relief
The Lib Dems won a famous by-election victory in this-strongly Labour area of Scotland in 2006. Willie Rennie looks set to retain the seat, whether that is due to Clegg or Brown is debatable.
02:00 Haltemprice & Howden – Davis reporting for duty
Former shadow home secretary David Davis is almost sure to secure victory in this seat, which he also won in a by-election in 2008. His resignation from parliament over detention without trial put him firmly on the backbenches, but it is thought only a matter of time before he is in government.
02:00 Slough – Come friendly bombs
The unloved Berkshire town may provide a rare bright moment for Labour. Surrounded by blue seats, it looks like Fiona Mactaggart may live to fight another day, despite the seat being Tory until 1997.
02:00 Stourbridge – Margot's on her way
A very impressive Tory woman is expected to be elected in this constituency, replacing Labour's Lynda Waltho.
Entrepreneur Margot James is exactly the sort of Conservative David Cameron is so keen on, so expect to see her on the frontbench in no time.
On the campaign trail with Margot James
02:00 Wyre Forest – Is there a doctor in the House?
There may be one less doctor if the Tories succeed in finally prising this seat out of the hands of independent Dr Richard Taylor.
Since his shock win in 2001 on a single issue – the local hospital – this mild-mannered former consultant rheumatologist defied expectations and won again in 2005. However, it looks like the party might be over.
02:30 Sheffield Hallam – Cleggmania!
Nick Clegg should be the second party leader to learn his fate, and will be hopeful of adding to his 8,682 majority given his increased personal profile.
And the Liberal Democrat leader will be ended his nationwide election tour in the city last night, where he held an election rally.
Expect lots of talk of a changed political landscape in his victory speech, despite it only being 2:30am.
02:30 Aberconwy – Welsh Tories back in fashion
Tory candidate Guto Bebb is expected to win this seat, previously held by Labour's Betty Williams. Formerly a safe Conservative seat, it should be another example of a surge in Wales from the Tories.
02:30 Blaenau Gwent – Of independent mind
This was once the safest of safe Labour seats, previously represented by iconic Socialists such as Michael Foot and Aneurin Bevan. However, a bitter local row over an all-woman shortlist in 2005 saw Peter Law elected as an independent.
His People's Voice party held the seat after his death in 2006 and looks set to do so again – the bookies give Labour 44 per cent chance of winning and People's Voice 51 per cent. Very local but definitely one to watch.
02:30 Cardiff North – Defeat of the First Lady
If as expected the Tory Jonathan Evans takes Cardiff North from Julie Morgan, it will be a significant moment.
Morgan was the ‘First Lady' of Wales for the decade her husband Rhodri was the country's first minister.
02:30 Gedling – Vernon's tricky situation
Schools minister Vernon Coaker is facing a strong challenge in this Nottinghamshire seat, with the bookies favouring his Tory opponent Bruce Laughton.
He could well be another ministerial scalp, but by this stage it should be clear if the Tories are on the road to overall victory or not.
02:30 Grantham & Stamford – Boles them over
He is a key member of the backroom team at Cameron HQ, but until now Nick Boles has been very much in the shadow of close contemporaries such as Michael Gove.
That is expected to change tonight when he reclaims Grantham, the town of Thatcher's birth, for the party, after sitting Tory MP Quentin Davies joined Labour in an rare bout of Brown-mania.
Expect to see Boles in a key role if the Tories form a government.
02:30 Harlow – Working class Tories
This seat was yet another of the Labour cull of 1997, but it is seen as solid working class Tory territory this time around.
Minister Bill Rammell is likely to be another high-profile scalp, with the bookies almost certain Conservative candidate Robert Halfon will be coming to Westminster.
03:00 Croydon Central – A highly-marginal affair
David Cameron's hopes of adding this highly marginal south London seat to his tally were dealt a blow when the sitting Independent MP Andrew Pelling reversed his decision to not contest the election.
Pelling, elected as a Conservative in 2005, was suspended from the party in 2007 over allegations made against him by his wife.
No charges were brought but Pelling decided to continue to sit as an Independent MP for the second most marginal seat in the country – his majority is a tiny 75.
His decision to contest the election may split the Conservative vote and let Labour candidate Gerry Ryan in through the middle.
03:00 Luton South – That's Life!
If there was one MP who came to personify the expenses scandal it was Labour's Margaret Moran, who claimed £22,500 for treating dry rot at her partners home 100 miles from her constituency.
MP for Luton South since 1997, Moran decided to jump before she was pushed and is not contesting the seat this time.
And she did not help her reputation when she was caught offering her services to a fake lobbying firm during Channel 4 and the Sunday Times' undercover sting earlier this year.
As a direct result of the expenses furore several independent candidates are contesting the seat including former 'That's Life' presenter Esther Rantzen.
On the campaign trail with Esther Rantzen
03:00 Witney – Cameron assured of victory
David Cameron is likely to be the last of the three main party leaders to hear from his constituency.
The Conservative party leader's Oxfordshire seat is a Tory stronghold and has been represented by a Conservative MP since its creation in 1974.
Cameron holds it with a majority of 14,156. His victory speech may or may not be a pledge to form the next government.
03:00 Antrim South – Empey makes his debut
The Tory pact with the UUP has provoked controversy within the Unionist ranks, and Antrim South presents their only realistic chance of picking up a seat tonight.
Their only sitting MP Sylvia Hermon walked out over the pact and is almost certain to be re-elected as an independent in South Down (see below).
So Sir Reg Empey, one of the oldest faces on the Belfast scene, looks set to become a new MP at the age of 63, under Cameron's banner of change.
03:00 Ashfield – the GMTV factor
Whatever the ins and outs of her selection, glamorous former GMTV journalist Gloria De Piero is bound to make a splash if, as expected, she wins Geoff Hoon's old seat tonight.
Lobby colleagues know her formidable skills will not go unnoticed by Labour's leadership.
03:00 Belfast South – The old green vs orange
All Irish eyes will be on this key seat tonight as the SDLP's Alasdair McDonnell fights to hold on to his seat in the face of Unionist foes.
The plural is significant because the two main Unionist parties did not come to an agreement here, as they did in Fermanagh and South Tyrone, to try to unite their vote to keep a nationalist out (see below).
With a split opposition, it looks like the well-liked McDonnell could be returning to Westminster.
03:00 Carmarthen West & Pembrokeshire South – the Wild, Wild West
Out on the very western edge of Wales, this largely rural seat is expected to turn blue, as it was until 1997.
It encompasses some of the UK's finest beaches, such as the five at Tenby, and is popular with those most reliable of voters, pensioners.
03:00 Dover – Wave the blue flag
Another seaside seat, another Tory recapture from 1997. The luxuriously-named Charlie Elphicke looks set to arrive at Westminster like an early Christmas present for sketch-writers.
03:00 Down North – Sylvia's lair
Lady Sylvia Hermon is expected to win back her seat as an independent, a testimony to a level of personal popularity few at Westminster could even dream of.
She left the UUP over their electoral pact with the Tories, and while viewed as more left-leaning than many Unionists, she is a powerful voice for that community, albeit from a constituency that is famous as the place where the haves meet the have yachts.
03:00 Down South – St Margaret
Another redoubtable Irish woman, this time from the green side. Margaret Ritchie is set to hold this seat for the SDLP – she was elected party leader earlier this year.
A moderate nationalist voice from a constituency that bore the brunt of the Troubles, her calm, devotional quality should win her friends at Westminster.
03:00 Fermanagh & South Tyrone – Sectarian chess
David Cameron said he would bring a new politics to Northern Ireland when he formed his electoral pact with the UUP.
But the backroom deal struck by the DUP and UUP to both back an independent Unionist in this constituency struck many as sectarian fixing of the oldest kind.
The target is Sinn Fein's abstentionist MP Michelle Gildernew. This seat, once won by hunger striker Bobby Sands from his prison cell, has deep significance for both sides of the divide, and has been closely fought over.
03:00 Glasgow East – Braveheart beaten back
The SNP's John Mason nipped into this safe Labour seat in a dramatic by-election win in 2008, but it looks likely to revert to its old ways tonight.
Mason has earned a reputation as a thoughtful, engaged and principled MP, so he will be missed in the Commons if he loses tonight.
03:00 Morley & Outwood – Castration strategy
Children, schools and families secretary Ed Balls is fighting for marginal Morley and Rothwell, following the abolition of his ultra safe Normanton constituency.
Antony Calvert is standing for the Conservatives, in a seat that is targeted by them in order to achieve their own version of a 'Portillo moment'.
To win in the newly-created constituency, Calvert will need a 10.5 per cent swing from Labour to the Tories.
03:30 Birmingham Erdington – Welcome Mr Harman
There was some disquiet when Harriet Harman did not insist upon an all-woman shortlist in this seat – especially when her husband Jack Dromey was selected instead of a Labour lady.
Union honcho Dromey has long been a behind-the-scenes player within the party – Westminster watchers will be intrigued to see Mr and Mrs Dromey at work in the very public venue of the Commons.
03:30 Brighton Pavilion – Green shoots
One of the moments of the night could be the election of Britain's first Green MP.
Green Party leader and MEP Caroline Lucas is fighting a close battle with her Conservative and Labour rivals in this seat on the Sussex coast.
In 2005 the Greens narrowly missed out on second place here, falling behind the Tories by just 894 votes.
On the campaign trail in Brighton Pavilion
03:30 Brighton Kemptown – Courting the pink vote
Labour look set to lose their second Brighton seat, this time to the Conservative candidate Simon Kirby.
This constituency has the largest LGBT population in the country, so it will be a key indicator of whether David Cameron's overtures to the gay community have been well-received.
04:00 Barking – BNP's only, distant hope
For decades, Barking and Dagenham has been considered a secure stronghold for Labour, but no longer.
The British National Party has made considerable strides in the outer east London area in recent years, gaining 12 out of 54 council seats in the borough.
In 2005, Labour's Margaret Hodge won the seat with a majority of 12,183, but the BNP, which is fielding Nick Griffin this time, came third with 16.9 per cent of the vote.
On the campaign trail in Barking
04:00 Crawley – smallest majority
Local radio station presenter Chris Oxlade is defending the smallest majority of any Labour-Conservative marginal in the country.
Laura Moffatt, Crawley's Labour MP for the past 13 years, won the seat in the last election with a majority of 37, a number she has tattooed on her ankle.
Oxlade, just a year older than the Labour majority in the town, was hurriedly selected as candidate following Mofatt's decision to stand down three weeks before the election was called.
04:00 Richmond Park – Zac attack
One of London's most affluent areas, Richmond Park is a key target for the Conservative Party, who aim to overturn Lib Dem Susan Kramer's 3,700 majority.
Zac Goldsmith is standing for the Conservatives, in one of the key 23 marginals the Tories must win from the Lib Dems in order to form a government.
He has declared that should the party win and a Cameron government goes back on its pledge to scrap a third runway at Heathrow, he will resign and force a by-election.
04:00 Dagenham and Rainham – Citizen Cruddas
Labour's Jon Cruddas is battling the BNP in this constituency, but he faces a tougher battle with Conservative Simon Jones. Cruddas, who has leadership ambitions, is expected to survive.
The BNP's sole member of the London Assembly, Richard Barnbrook, has fought an unimpressive campaign, though a close eye will be kept on the Barking and Dagenham local elections in the borough on the same day.
04:00 Edinburgh North & Leith and Edinburgh South – Lib Dem territory
These previously Labour seats look likely to fall to the Lib Dems, and should be among the 20 or so new Lib Dem seats in the new parliament, if the polls are accurate.
Edinburgh South, previously represented by Nigel Griffiths, has been held by Labour since 1987.
04:00 Watford – the weathervane constituency
All three main parties have a real chance of winning the Hertfordshire town, amid a broader national indecisiveness. There are only 2,000 votes between the three candidates and it's both a Liberal Democrat and Tory target seat.
Labour's Claire Ward was elected as the youngest female MP, then aged 24, in the 1997 landslide. Embroiled in the expenses scandal, Ward defends a 1,148 majority.
04:00 Hammersmith – Shaun's dawn
Tory poster-boy Shaun Bailey is seen as a totem of the changed Cameron party. So all eyes will be on this west London seat to see if Bailey will be elected.
Labour's Andrew Slaughter has been fighting hard, but the bookies favour his young, urban and black opponent.
04:00 Harrow East – Expenses could swing it
The expenses scandal could be one of the central issues for candidates in Harrow East, defended by Labour's Tony McNulty, who was ordered to repay £13,837 following claims on his parents' home in Hammersmith, which was designated as his second home.
McNulty has held the seat since 1997, but the Tories need just a 3.4 per cent swing in their favour to turn the seat blue, placed on their target list of seats.
04:00 Islington South & Finsbury – Emily's list
Labour managed to hold off the Lib Dems – just – in 2005, but Emily Thornberry must be worried she will not be so lucky this time. Her opponent Bridget Fox has been working the constituency with the thoroughness of a prison warden – this will be a close fight.
Despite the association with New Labour, it contains some of the worst pockets of deprivation in London, and Thornberry is hoping her assiduous casework will have won her new supporters.
04:00 Poplar & Limehouse – Gorgeous George's spoiler tactics
Minister Jim Fitzpatrick could have been forgiven for thinking his east London seat would be safe – that was before George Galloway appeared on the scene. Carpet-bagging in from next-door Bethnal Green, feline impersonator Galloway is aiming to snatch the Muslim vote from Fitzpatrick.
That could well result in the Tories winning their first seat in the East End of London in a century.
04:30 Bedford – three-way split
The urban seat of Bedford sees a three-way fight – youthful Lib Dem candidate Henry Vann is desperately hoping the Clegg effect will sweep all before him.
The bookies however think Tory Richard Fuller will be on his way to Westminster, with Vann second and former MP Patrick Hall for Labour placed third.
04:30 Liverpool Wavertree – Billy Shankly's ghost
Labour's Luciana Berger had a grim start to her campaign when she revealed her ignorance of Liverpool's football and music history in an interview with a local paper.
Scouse actor Ricky Tomlinson floated the idea of running against her. In the end he didn't, but Berger's woes may be compounded by the Clegg effect ushering her Lib Dem opponent into office.
04:30 Liverpool West Derby – Twigg redux
Stephen Twigg became an overnight star when he beat Michael Portillo in the 1997 election. He lost Enfield Southgate in 2005, but is returning to frontline politics via this safe Labour seat.
He will undoubtedly be a leading figure in the party after the election, and tonight will mark the start of his journey back to power.
05:00 Redditch – Jacqui's moment
Former home secretary Jacqui Smith defends a 2,716 vote majority over the Conservatives.
Controversy surrounding Smith's expenses claims may increase opposition support in this seat.
Her humiliation at the hands of her husband may sway some voters, but unfortunately for one of Labour's most high-profile women the odds are against her.
05:00 Chorley – Labour heartland?
Lindsay Hoyle, a loud, cheeky and popular figure in the Commons, has a fight on his hands to retain this increasingly-affluent Lancashire seat. Bookies predict Tory candidate Alan Cullens will win, but only just.
Wags suggest Hoyle could join his dad, former MP Doug, in the House of Lords.
05:00 Ealing Central & Acton – New seat, new party
This newly-created seat in West London looks likely to be won by Tory Angie Bray. Winning the capital is key to Cameron's strategy – this will be a welcome early-morning boost.
By now it should be clear who, if anyone, has won a mandate to govern.
05:00 Brent Central – the mother of all battles
Lib Dem Sarah Teather and Labour's Dawn Butler have been battling for control of this north London seat for years – on Friday morning there can only be one victor.
The bookies have the candidates neck-and-neck, so it should be one of the most exciting results of the night.
05:00 Westminster North – Cashing in
A seat containing extremes of poverty and wealth, the affection felt for Labour MP Karen Buck may see her through against Conservative Joanne Cash.
Buck, a dedicated grassroots community champion, could lose the seat with just a 3.5 per cent swing to the Conservatives.
Cash also courted controversy by resigning in a spat with her constituency chairman and only returning as a candidate after high-level interventions from Tory HQ. She denies she is a Cameron insider.
05:30 Corby – Chick-lit victory?
Chick-lit novelist and ultra-Cameron loyalist Louise Bagshawe looks likely to win this Northamptonshire seat from minister Phil Hope.
Bagshawe is likely to be a Commons sketch-writer's dream, if she can convince voters, many of whom live in serious deprivation, to back her.
06:00 Hampstead & Kilburn – Oscar winning performance
In 1992 Glenda Jackson, winner of two Academy Awards, won the seat from the Conservatives, who had held it since 1974. Jackson increased her majority to more than 13,000 in 1997 and retained the seat in 2001 and 2005, latterly with a majority of 3,729.
At 73, Jackson is fighting to stave off a threat from the Liberal Democrats in the newly redrawn cross-borough Hampstead and Kilburn constituency.
Friday 14:30 Buckingham – Speaker seeks his voice
As Speaker, John Bercow is being a given a free run by the three main parties which are following convention and are staying away.
But then UKIP leader Nigel Farage announced he'd be standing against Bercow and would resign as party leader to focus on the campaign.
And one independent candidate, former MEP John Stevens, is campaigning with a dolphin called Flipper to remind voters that Bercow was one of many MPs who "flipped" their homes to claim different expenses.
Despite this torment, the Speaker is expected to be back at Westminster, where he could face a second electoral test – one to decide whether he will take the chair again.
