A celebrity doctor due to stand in the next general election stepped down just days after denying rumours he planned to quit after falling out with his party.

Tory Dr David Bull, who pulled out of the running for the Brighton Pavilion parliamentary seat on Friday, had been approached by The Argus a week earlier.

Rumours had spread he wanted to step down and had openly spoken about his departure.

Asked by The Argus about the stories, Dr Bull said: "You're the third journalist to ask me that. I don't know where it has come from but it's not true."

But on Friday his departure from the candidacy was officially announced as part of a message on the Conservative website naming him as part of a review of sexual health planned by the party.

When The Argus called Dr Bull yesterday about the announcement he apologised for his previous response.

He said: "I'm sorry I had to say that. I ve been asked by Andrew Lansley and David Cameron to head up a policy review on sexual health.

"It's fantastic news for me because I've done a lot of campaigning around the subject."

He said his increased workload meant he would not have time to continue his election bid.

Dr Bull said: "I have my company and the policy review with Pavilion as well it was too much.

"I may be good but I'm not superman. Something had to give."

Dr Bull was a high-profile Conservative on the party's A-list of national candidates.

He has presented BBC's Newsround, Watchdog Healthcheck and Tomorrow's World and is a panellist on The Wright Stuff on Five.

He also runs a PR and communications consultancy.

He was picked to contest the seat in December 2006 and set about working to win over voters who had given Labour's David Lepper a 6,000 vote majority the previous year.

The openly gay candidate's campaign involved an elaborate float during Brighton Pride in 2007, during which he wore a T-shirt with the slogan "I've come out . . . I'm a Tory."

However, he stopped blogging on his campaign website in February shortly after moving from London to Brighton.

National newspaper columnists have questioned the timing of his departure on the day of Michael Jackson's death, suggesting it may have been deliberately set up to bury the story.

Dr Bull denied the accusation, along with suggestions his departure was due to a falling out with local Conservatives.

He said his move had only been agreed in the week before he stepped down.

Carol Ramsden, chairman of Brighton Pavilion Conservative Association, also denied suggestions of a falling out.

She said: "We are very sorry to see David step down but we are proud he will be leading such an important policy area for the party and understand the demands on his time."

The party will chose a new candidate in the next few months, leaving less than a year for them to prepare for a general election."

Nancy Platts, who will replace the retiring Mr Lepper as Labour's candidate for Brighton Pavilion, berated the Conservatives for the way they had treated the city.

She said: "This just proves David Cameron's celebrity A-list isn't working.

"They shouldn't think they can just parachute someone in like that."