Ann Widdecombe, the shadow Home Secretary and a committed Christian, said she would support a comeback by the former Secretary of State for Defence.
"Obviously for religious reasons I believe that homosexuality is wrong, but as far as Michael Portillo goes it is not my business," she said in a television interview.
"I don't pass judgement on individuals. My view is that Michael Portillo is an extremely able ex-colleague and I look forward to the occasion when he becomes a colleague again."
A Sunday newspaper tracked down Mr Portillo's ex-lover after the politician revealed last week that he had homosexual experiences as a student. The former MP, who lost his Enfield Southgate seat at the 1997 general election, hopes to return to political life in the Chelsea and Kensington by-election caused by the death of Alan Clark.
Nigel Hart, a company director, told the Mail on Sunday that he had an on-off relationship with Mr Portillo which spanned eight years. The two men met at a party in London when Mr Portillo was 18, but did not consummate their relationship until a year later, when the future MP was a student at Peterhouse, Cambridge.
Mr Hart said when the two men first started seeing each other Mr Portillo was also going out with Carolyn Eadie, his future wife. Later he had other girlfriends but met Carolyn again after leaving Cambridge University and going to work in London.
By an extraordinary coincidence, Carolyn bought a flat that Mr Hart had renovated for sale. They soon discovered their mutual acquaintance, and Mr Portillo found it amusing that his two lovers lived under the same roof, Mr Hart said.
Even after Mr Portillo's marriage and the end of his relationship with Mr Hart, the three remained friends. When Mr Hart's business collapsed in 1984 he lived with the Portillos in Clapham for six months.
They fell out, though, when Mr Portillo voted against lowering the homosexual age of consent to 16 in 1994. Mr Hart, an equal rights campaigner, wrote to his friend: "If the course of your life during your twenties was publicly known it would be almost inconceivable that you could become Prime Minister. I doubt you could even stay in politics."
Mr Portillo was not available for comment yesterday.Reuse content