The House of Lords last night overturned the massive Commons vote in favour of lowering the age of consent for gay men from 18 to 16. On a free vote, the Lords agreed by 290 votes to 122, majority 168, to strike out the measure from the Crime and Disorder Bill.
The vote comes as a major blow to gay rights activists who only last month celebrated when MPs voted by a 207-majority to equalise the age of consent for male homosexuals with that for heterosexuals.
The move sets peers on another constitutional collision course with the Commons, ahead of the abolition of hereditary peers' rights to sit and vote in the Lords.
Ministers will now have to decide whether to try to reverse the setback in the Commons before the summer recess starts at the end of the month.
There have been reports that the government will drop the age of consent measure from the Bill rather than see its fast-track plans to combat crime delayed.
The Tory former cabinet minister, Baroness Young, with cross-party backing, spearheaded the move to vote down equalising the age of consent. Ignoring government pleas not to block the measure, and protests from gay demonstrators outside Parliament, she branded the change "seriously flawed".
Winding up the debate, she said: "I've only stood up on this issue because I care very much about young people.
"I would feel I was failing in my duty if I didn't say that lowering the age of consent without proper parliamentary scrutiny would be quite wrong - constitutionally and in principle."
Her cause was boosted by the Archbishop of Canterbury, Dr George Carey, who was not present for the debate but earlier yesterday said lowering the age of consent for homosexuals would be a "grave error" and morally unhealthy. The Lords was crowded for the impassioned three-hour debate, with Tory former Prime Minister Baroness Thatcher listening intently alongside Lady Young.
Moving her amendment, Lady Young said lowering the age of consent was "wrong in principle" and "not wanted by the public at large".
Warning that "homosexual practises carry great health risks to young people," she complained the Commons amendment had been "tacked on", hardly allowing any debate.