Hartley Booth resigned as a parliamentary private secretary to Douglas Hogg, the Foreign Office minister of state, after newspaper reports of a relationship with a House of Commons researcher, Emily Barr.
Mr Booth, a 47-year-old Methodist lay preacher who is married with three children, said in a statement last night: 'There was no sexual impropriety. But in all the circumstances I am resigning as parliamentary private secretary in the Foreign Office.'
Ms Barr, aged 22, is the Guardian Student Journalist of the Year and had also worked for other politicians including Peter Mandelson, Labour MP for Hartlepool. She is a history of art student at the Courtauld Institute in London.
Mr Booth's decision will provide another jolt to John Major's battered Government following recent scandals involing two ministers, and the death last Monday of the MP Stephen Milligan.
Observers viewed Mr Booth's snap resignation as a response to Mr Major's recent warning to colleagues that members of the government should quit if they transgressed.
The damage to the Government since Mr Major's 'back to basics' initative began to backfire is illustrated by a Gallup poll in today's Sunday Telegraph which suggests that 64 per cent of voters, including more than a quarter of Conservatives, believe that the Tories give the impression of being 'very sleazy and disreputable'.
The chairman of the Finchley constituency association, Ron Thurlow, last night said that the party stood by the MP adding: 'He certainly has not had an affair as such. There has been no sex involved and it is rather a fuss about nothing.'
Mr Thurlow told Sky News: 'He has been in touch. He phoned me at midday and told me the story.' Mr Booth disputed parts of reports which appeared in several newspapers.
Mr Hogg said: 'Hartley is a good friend and colleague. I am extremely sad he felt he had to resign. He has considerable political skills and I hope this is only a temporary setback.'
It was emphasised that there was no question of the MP resigning his seat, where his majority over Labour in a six- cornered contest at the last election was 6,388.
Mr Booth becomes the eighth Conservative parliamentarian since the general election whose personal life has been the subject of allegations. The others include David Mellor, who was forced to resign as National Heritage Secretary; Tim Yeo who quit as junior environment minister because of his affair with a Tory councillor; Steve Norris, a transport minister; and Lord Caithness who resigned as a minister in the Lords. Backbenchers who have been the subject of scandals include David Ashby and Garry Waller.
In the wake of the Government's sustained unpopularity, the Conservatives may break parliamentary convention by postponing the Eastleigh by- election, caused by the death of Stephen Milligan, until June.
Ministers and government business managers are keen to delay the poll until 9 June, the date of the European elections, rather than hold it on 5 May, local election day, as expected.
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