The cull of senior staff at Conservative Central Office has continued with the news that Vanessa Gearson is to leave her post.

Gearson, the party's deputy director, has also been selected as the party's candidate for Cheltenham at the next general election.

But she she is best known as the official at the centre of the "Betsygate" row.

Parliamentary standards commissioner Sir Philip Mawer is continuing his investigation into claims that former Tory leader Iain Duncan Smith wrongly employed his wife as secretary.

Dr Gearson has given evidence to Sir Philip, after initially raising concerns about Mrs Duncan Smith's work.

In a confidential memo, which was subsequently made public, she warned against a "Crick-style investigation" into Duncan Smith's office arrangements.

Tim Harman, chairman of the Cheltenham Conservative Association, insisted that her departure was "normal procedure".

"It is normal procedure when you have a new leader. They like to bring their own people in," he said.

"She leaves with a lot of goodwill and we obviously welcome the fact she will be able to devote more time to the constituency."

Gearson is the fourth senior Tory to be removed under the new leadership.

Paul Baverstock, who was drafted in by Iain Duncan Smith as director of strategic communications, is to leave Smith Square.

Seen as a mediawise operator he was known to text senior Conservatives to remind them to smile during television appearances.

Likened to a Tory Alastair Campbell, he was responsible for an earlier clear out at Smith Square.

He is joined at the exit door by media director Nick Wood, who was recruited by William Hague.

A former lobby journalist with The Times and the Daily Express, 52-year-old Wood is a well known figure in Westminster media circles.

Wood played a key role in the 2001 general election and was promoted after Duncan Smith's election as Tory leader.

Nick Longworth, the party's head of broadcasting, will also be leaving Central Office.

Speaking on Wednesday, Tory chairman Dr Liam Fox said: "On behalf of the board, I would like to express my sincere thanks to Paul, Nick and Nick for their work on behalf of the party.

"Paul Baverstock has made a major impact over the last year developing our political and communications strategies.

"Nick Wood has given outstanding and devoted service to two leaders of the party over the last five years.

"And Nick Longworth has played a leading role in improving our broadcasting operation. We wish all three of them the best for the future."

On Tuesday the party's governing board announced that they are looking to sell the lease on Central Office.

Party managers are now in the market for modern office accommodation in the Westminster area.

Tory sources have not ruled out a move into Millbank tower, the former office block once occupied by New Labour.