London, England - Christians, Muslims and Jews will demonstrate outside Parliament today against new homosexual rights laws that they claim will force them to "actively condone and promote" gay sex.
A petition signed by 10,000 Christians will also be handed to the Queen asking her to use her "position and power" to stop the Government introducing the laws.
The protests will coincide with a House of Lords debate on the Northern Ireland Sexual Orientation Regulations, which are designed to prevent businesses discriminating against gays in the provision of goods and services.
But critics say they undermine freedom of religion and conscience and could have a serious impact on faith schools, charities and adoption agencies.
The campaign is backed by Christian lawyers, including Lord Mackay of Clashfern, the former Lord Chancellor, and senior Church of England and Roman Catholic bishops.
Writing in The Daily Telegraph today, Lord Mackay said that the regulations would affect "the individual seeking to practice his faith in his daily life".
He said: "The regulations aim to over-ride his conscientious objections in the interest of promoting the freedom of those who wish to indulge in homosexual practices."
In the debate this evening, peers will vote on a motion calling for the regulations to be annulled because they undermine freedom of religion and conscience. The Government is planning to introduce them across England, Scotland and Wales in April, but they came into force in Northern Ireland on Jan 1 under direct rule powers.
Thomas Cordrey, a barrister with the Lawyers' Christian Fellowship, said: "The debate is a signal to the Government of the need to acknowledge that these regulations do not strike the correct balance between competing rights.
"Christians have no desire to discriminate unjustly on the grounds of sexual orientation, but they cannot and must not be forced to actively condone and promote sexual practices which the Bible teaches are wrong. It is a fundamental matter of freedom of conscience.
"It is possible for these regulations to outlaw discrimination, whilst guaranteeing the freedom for religious believers to abide by their faith."
But the Trade Union Congress urged the Government to resist lobbying from religious organisations to dilute the regulations.
Brendan Barber, the TUC general secretary, said: "No one should be denied a room in a hotel or the right to adopt simply because of their sexual orientation. But this is what some religious leaders believe should happen and they are pressurising the Government to continue to allow lesbians and gay men to be treated as second-class citizens."