The number of registered voters is declining at a time when the population is rising, according to the latest figures.

The Office of National Statistics reported that there are now 44.1 million voters in the UK, 500,000 fewer than two years ago.

The number of voters fell by more than 10 per cent in four parliamentary constituencies - Bolton South East, Lewisham Deptford, Portsmouth South and Slough.

Only three constituencies - Nottingham North and Nottingham East and Stockton South - recorded increases of more than five per cent.