Iain Dale, the Conservative blogger, has said he will no longer attempt to become an MP.
The 47-year-old, who will be 52 at the next election if parliament lasts five years, said older candidates are “very much the exception rather than the rule”.
Mr Dale attended the Pride reception at Downing Street last night.
Writing on his blog, he said the prime minister told him he hoped he would try again to win selection for a seat.
Mr Dale said he replied that he had already made a decision not to stand again.
He stood as a candidate for Norfolk North in 2005 and was the first openly gay candidate selected by a Conservative constituency association. However he lost out to Liberal Democrat candidate Norman Lamb.
In 2007, he unsuccessfully applied for the safe Conservative seat of Maidstone and the Weald.
Last October, he made it to the final seven to be the Conservative parliamentary candidate for Bracknell but was not selected.
Mr Dale said: “I’ve made my views known before about the virtues of selecting older candidates, with real life experience, but politics in this country is becoming youth obsessed and I doubt whether I would be able to stem that particular tide.
“Of course older candidates do get selected, but they are very much the exception rather than the rule – exactly the opposite of how it should be.”
He said he would continue to help the party in a voluntary manner but had written to party chair Sayeeda Warsi to ask her to remove his name from the party’s list of approved candidates.