Trade unions, religious leaders and MPs joined a growing coalition yesterday calling for illegal immigrants who have been living in Britain for a number of years and who can prove they have contributed to society to be allowed to stay.
At a public assembly in Westminster last night, all four of London's main mayoral candidates pledged their support for the plan.
Liam Byrne, the Immigration Minister, has opposed the calls, saying it would lead to a unmanageable surge in immigration. And David Cameron, the Tory leader, has distanced himself from the stance of Boris Johnson, the Tory candidate for Mayor.
Jack Dromey, deputy general secretary of Unite, Britain's largest trade union, said politicians "should be brave and allow that twilight army to emerge into the open".
The proposals demand that would-be citizens pass strict tests before gaining full citizenship. These include having no serious criminal record and being willing to learn English.
But the Home Office said there would never be an amnesty and that it would continue with its efforts to remove illegal immigrants.
The amnesty plan is also supported by Christian and Muslim leaders.