MPs have voted to lower the age of consent for gay men from 18 to 16 - with shadow chancellor Michael Portillo backing the move for the first time.

The legislation was agreed in the Commons by 263 votes to 102.

The bill now goes to the House of Lords, where it is likely to face sterner opposition - with the government ready to use special powers to force it through Parliament.

Mr Portillo, who voted against the move in 1994, was under pressure to support lowering the gay age of consent after admitting having had "some homosexual experiences" as a student when he was under the then age of consent of 21.

Opening the debate on Thursday, Home Secretary Jack Straw said cutting the age of consent for gay men to 16 would create a society free from prejudice where people do not live in fear.

The sexual offences (amendment) bill would end the anomaly that heterosexuals and lesbians can consent to sex at 16 while gay men have to wait until 18.

The bill would also reduce the age of consent for gay sex to 17 in Northern Ireland.

And it introduces a new offence where someone over 18 - such as a teacher - can be prosecuted for an abuse of trust by having sex with a youngster in their care.

Mr Straw told MPs: "For me the issue raised in this bill is one of equality, of seeking to create a society which is free from prejudice, of one where our relationships with others, including with strangers, are based upon respect and not upon fear."

Shadow Home Secretary Ann Widdecombe warned the bill was a "dangerous move," sending the wrong signals to teachers, parents and young people.

She said: "It is wrong that a young person of 16 should be free in law to embark on a course of action that might lead to a lifestyle which would separate him, maybe permanently, from the mainstream life of marriage and family."

'Big trouble'

Liberal Democrat Home Affairs spokesman Simon Hughes said his party had campaigned for a lowering of the age of consent since it was formed in 1988.

He said: "You cannot say to gay people that you value them as equals if the law does not treat them as equals. If in the year 2000 we cannot move forward, my friends we are in big trouble indeed."

Mr Portillo's change of heart was welcomed by Peter Tatchell of the gay pressure group Outrage, who said: "Outrage welcomes Michael's vote for equality - we have always wanted him to be a supporter of the gay community rather than an opponent.

'Misery and fear'

"I hope he will now follow up his opposition to a discriminatory age of consent by voting for the repeal of Section 28."

Another Tory also changed his position on the issue. Buckingham MP John Bercow said he was now convinced the current law was a "recipe for confusion, for misery and for fear".

The government is introducing the move after a ruling that the existing law was a breach of the European Convention on Human Rights.

The House of Lords has twice rejected the proposal since 1997.

However, even if peers do throw out the plan, Mr Straw is likely to use the Parliament Act to force it into law.

The bill comes hard on the heels of the government's defeat by peers this week over plans to repeal Section 28, which prevents local authorities from promoting homosexuality.