Boris Johnson reopened the debate over how to deal with hundreds of thousands of people working illegally in the UK, insisting that simply deporting them was "not going to happen". Johnson's comments risk opening a rift between himself and Tory leader David Cameron, with whom he openly clashed on the issue of an amnesty earlier this year. Speaking to Channel 4 News, the Conservative mayor said that allowing long-term illegal immigrants to earn the right to stay in Britain would see "hugely increased" tax revenues. Of the 700,000 thought to be working illegally in the UK, about 400,000 are in London. However, Immigration minister Phil Woolas said: "His comments might start with the best of intentions but will lead to more people traffickers making more money and exploiting more vulnerable individuals."