Mr Cameron also expressed "regret" that Lady Warsi announced her resignation on Twitter at 9.10am without first having a conversation with him. Mr Cameron was beginning a family holiday in Portugal when he heard the news. With deep regret I have this morning written to the Prime Minister & tendered my resignation. I can no longer support Govt policy on #Gaza — Sayeeda Warsi (@SayeedaWarsi) August 5, 2014 Mr Osborne called the resignation "disappointing and frankly unnecessary" and pointed out that a 72-hour ceasefire was announced shortly before her decision But several prominent Conservative MPs backed her position, threatening a split in the party over Gaza ahead of the election.

Opposition Labour leader Ed Miliband said Lady Warsi had "acted with principle and integrity" over the issue. He called on Mr Cameron to "break his silence and say that Israel's actions have been unjustified and indefensible". One senior minister described Lady Warsi's resignation as "ridiculous" and claimed her resignation "had little to do with Gaza". Lady Warsi rose to office in 2010 as a minister without portfolio and co-chairwoman of Mr Cameron's Conservative Party. But she was demoted in a reshuffle in 2012, becoming a junior minister in the Foreign Office, albeit with the right to attend cabinet meetings. Some analysts said that the resignation also reflected Lady Warsi's unhappiness with a major reorganisation of the government ordered by Mr Cameron last month, in which she was not restored to a higher office. In an interview with Channel 4 News, Lady Warsi accused Mr Cameron of a "mealy-mouthed" response to the conflict, which has left nearly 2000 people dead. She accused the government of "dragging [its] feet" and said that she has spoken to an MP who was "in tears" about the government's failure to act.

Warning of another ministerial resignation, she added: "I've had a minister in a late-night conversation talking about resignation. There is real concern amongst Conservatives on this issue." Nick Clegg, the Deputy Prime Minister, risked a coalition row by appearing to back Lady Warsi's stance when he called for a suspension of arms export licences to Israel. In her resignation letter, Lady Warsi said the "language during the current crisis in Gaza is morally indefensible, is not in Britain's national interest and will have a long-term detrimental impact on our reputation internationally and domestically". She said that the Home Office has "evidence" that British Muslims could be radicalised by the conflict and travel to fight in the region. Her letter was also highly critical of Mr Cameron, with a thinly veiled attack on last month's reshuffle and the sacking of moderates including Ken Clarke, the former minister without portfolio, and Dominic Grieve, the former attorney-general.

She was also critical of Philip Hammond, the new Foreign Secretary, warning that there is "great unease" in his department about "the way recent decisions are being made". Mr Hammond said he found it "rather surprising that she's chosen now, this particular moment, to take this stand, when in fact we are now at long last seeing some relief [in Gaza]". Lady Warsi said the conflict could lead to "consequences for us for years to come" and that the issue could be as much of a threat to Britain as the situation in Syria and the Islamic State extremist group in Iraq. She added: "It's not a claim that I make. It's the evidence which is there in black and white from the work that the Home Office is doing."

Loading But a source close to Theresa May, the Home Secretary, said: "We don't have any research that shows that Gaza is having a radicalising effect in Britain." Telegraph, London; Reuters; New York Times