MICHAEL Portillo's political comeback in the wake of his admission to a gay past suffered a major jolt last night when his former homosexual lover - allegedly of eight years - came forward and denounced the former Tory Defence Secretary as a hypocrite.

Mr Nigel Hart explained that their relationship turned frosty when in 1994 Mr Portillo voted in the Commons against lowering the age of gay sex to 16.

It was in 1972 that the two men are reported to have begun their sexual affair. Since at the time, the age of consent for homosexuals was then 21, the act was technically illegal as Mr Portillo was 19 at the time.

Mr Hart said that in 1994 he wrote to his former lover, accusing him of hypocrisy and selfishness, but never received a reply.

The letter reportedly said: ''If the course of your life in your 20s was publicly known, it would be inconceivable that you could become Prime Minister. I doubt you could even stay in politics.''

However, Mr Hart said he had asked his lover during their affair if being gay would harm his political career. He claimed that Mr Portillo replied: ''The time will come when no-one will care.''

The new claims could do serious damage to the former Enfield Southgate MP's bid to become the Conservative Party's candidate and thereafter their MP for the true blue constituency of Kensington and Chelsea.

Firstly, Mr Portillo's admission to having had ''homosexual experiences'' in his youth understates a gay relationship in the 1970s that allegedly lasted eight years.

Secondly, the charge of hypocrisy: coming as it does from his former gay lover, this will in some people's eyes add weight to the charge. This could be far more damaging to Mr Portillo's credibility than the revelations themselves.

In an interview with the Mail on Sunday, Mr Hart said he and the young Portillo had sex in Cambridge, London and abroad during their on-off affair.

They had met in December, 1971, at a gay party held by a London University don when Mr Portillo was an 18-year-old schoolboy, said Mr Hart.

Mr Hart recalled: ''There was a lot of flirting at the party. The men were calling Michael ''Polly''. We flirted together and he seemed to find me attractive.''

But it was not until a year later that they consummated their relationship at Mr Portillo's rooms in Cambridge University's Peterhouse College, said Mr Hart.

''I felt he had other homosexual affairs. He wasn't experienced but he wasn't nervous. Sex was fun, but it was nothing remarkable,'' insisted Mr Hart.

The Cambridge graduate also said the pair had enjoyed sex together in a west London flat while Mr Portillo's girlfriend, Carolyn, lived upstairs.

However, he said she had known about their gay relationship.

He said Mr Portillo had found the idea of his two lovers living in the same building ''amusing''.

He had once turned round in the company of both and said: ''I've just worked out that the first time I slept with you was the day after I slept with Carolyn for the first time.''

Mr Hart said their relationship ended when Mr Portillo got engaged to Carolyn, but they remained good friends for many years and he had even stayed with them for six months in 1983 when his business collapsed.

Yesterday, Shadow Home Secretary Ann Widdecombe told GMTV that, while she believed homosexuality was wrong, she supported Mr Portillo's political comeback.

Meanwhile, two polls showed large majority backing for Mr Portillo's action in revealing his gay past.