The government's policy towards the Israeli incursion into Gaza was in danger of falling apart on Tuesday night in the wake of the surprise resignation of the Foreign Office minister Sayeeda Warsi and a demand by Nick Clegg that Britain immediately suspend arms export licences to Israel.
Lady Warsi said the prime minister had lost moral authority, undermined the national interest and deprived Britain of its historic role as an honest broker in the Middle East by refusing to condemn the aggressive Israeli response to the Hamas rocket attacks as disproportionate.
In her strongly worded resignation letter, whose morning publication came as a surprise to No 10, Warsi warned that "our approach and language during the current crisis in Gaza is morally indefensible [and] is not in Britain's national interest".
She also complained that Cameron's response may become "a basis for radicalisation [which] could have consequences for us for years to come".
Her departure came after internal argument inside the National Security Council over Cameron's refusal to condemn the aggressive Israeli response to the Hamas rocket attacks.
British ministers have condemned the outcome of the Israeli bombings as intolerable and appalling, but Cameron has barred ministers from describing the Israeli bombings as disproportionate, and refused to attribute final blame prematurely even for some of the attacks on UN schools in Gaza.
Warsi's departure exacerbated coalition tensions over Gaza, as Clegg urged an immediate suspension of arms export licences, saying that Israel had breached the conditions. He said the suspension should remain in force until agreement has been reached across the government on any permanent revocation in the coming days.
Ministers agreed a review of the licences last week, but Clegg has decided to ratchet up the pressure, saying: "I believe the actions of the Israeli military, overstepping the mark in Gaza, breach the conditions of those export licences and that's why we want to see them suspended pending a wider review of whether they should be revoked more permanently in the long run."
Revealing he has been putting pressure on his Conservative colleagues for a suspension of the licences rather than a review, he said: "I believe we will be able to make an announcement on this, finally, very shortly. It's very important that in response to clearly what appears to be disproportionate military action of Israel in Gaza, we should be suspending the arms export licences that presently exist."
Warsi's departure also prompted a vicious round of briefing against her by some Tories, condemning her variously as egotistical, incompetent, a Hamas sympathiser and motivated by pique at her failure to be promoted in the last reshuffle.
However, Downing Street, aware that she has the potential to cause lethal damage if she broadens her attack on the Cameron circle, as her resignation letter threatened, distanced itself from such briefings. Cameron, in his reply to her resignation letter, lavished praise on her and urged her to raise any issues with him in the future. It is known she has kept copious diaries, and officials fear she may claim in retrospect she was used as a token Muslim.
Cameron wrote: "I very much regret that we were not able to speak about your decision beforehand." He added: "I understand your strength of feeling on the current crisis in the Middle East – the situation in Gaza is intolerable. Our policy has always been consistently clear: we support a negotiated two-state solution as the only way to resolve this conflict once and for all and to allow Israelis and Palestinians to live safely in peace."
The departure of the first British Muslim cabinet minister is a major blow for Cameron, potentially weakening Conservative support among ethnic minorities in marginal seats, lifting the lid on the divisions on the Tory backbenches over the scale of Israel's bombing, and apparently confirming to the party's centre-left that traditional support for international human rights has been severely eroded by ministerial changes. "It's now a Daily Mail administration," complained one recently sacked Conservative minister.
Warsi, as senior foreign office minister, was responsible for British support for international human rights law and in her resignation letter bemoaned the departure in the previous reshuffle of Kenneth Clarke, and the former attorney general Dominic Grieve.
Warsi spoke at length to the new foreign secretary, Philip Hammond, on Sunday and appears to have held back from resigning on Monday because of the first world war commemorations.
Instead she resigned via Twitter just after 9am on Tuesday, coincidentally about three hours after a three-day ceasefire had come into force.
Both Hammond and the chancellor, George Osborne, highlighted the timing of her announcement. Osborne described her decision to quit as "disappointing and frankly unnecessary", while Hammond said he was slightly surprised she had quit just as weeks of behind-the-scenes diplomacy was bearing fruit with the ceasefire.
But Warsi's resignation broke a dam of criticism of Israel in the Conservative party. Boris Johnson, the London mayor often touted as a future leadership contender, condemned Israel with the words Cameron has declined to deploy.
"I believe in a two-state solution. I cannot for the life of me see how this helps us get there. I think that it is disproportionate, I think it is ugly, and it is tragic. And I don't think it will do us any good in the long run," Johnson said.
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