Pressure continues to mount on the Government to suspend arms sales to Israel following the deaths of three British aid workers in an airstrike in Gaza.

A letter published on Wednesday night and signed by more than 600 lawyers, including former Supreme Court justices, said the Government risked breaching international law by continuing to allow the export of weapons to Israel.

Signatories, including former Supreme Court President Lady Hale, said the worsening situation in Gaza and the International Court of Justice’s conclusion that there was a “plausible risk of genocide” obliged to UK to suspend arms sales to the country.

Other signatories included former Supreme Court justices Lord Sumption and Lord Wilson, along with nine other judges and 69 KCs.

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Three British nationals were among the seven aid workers killed when a World Central Kitchen convoy was bombed by the Israel Defence Force on Monday (AP Photo/Ismael Abu Dayyah)

The letter came at the end of a day of cross-party calls for the suspension of arms exports to Israel following the news that three British nationals were among the seven aid workers killed on Monday night.

Labour’s shadow foreign secretary, David Lammy, urged the Government to publish any legal advice it had received on whether Israel had broken international law, and to suspend arms sales if there was a risk weapons could be used in “a serious breach of international humanitarian law”.

He said: “The law is clear. British arms licences cannot be granted if there is a clear risk that the items might be used to commit or facilitate a serious violation of international humanitarian law.

“Labour’s message to the Government is equally clear. Publish the legal advice now. If it says there is a clear risk that UK arms might be used in a serious breach of international humanitarian law, it’s time to suspend the sale of those arms.”

On Tuesday, Downing Street declined to say whether it believed Israel was operating within international humanitarian law, saying it would not comment on legal advice but added ministers acted in accordance with any advice.

The SNP and the Liberal Democrats have also called for arms exports to be suspended, as have Conservative MPs Flick Drummond and David Jones following a similar plea from Lord Ricketts, the former national security adviser to now-Foreign Secretary David Cameron.

But Rishi Sunak said the UK had a “very careful” arms export regime that it would “always follow”.

He told The Sun newspaper’s Never Mind The Ballots show: “There are a set of rules, regulations and procedures that we’ll always follow, and I have been consistently clear with Prime Minister Netanyahu since the start of this conflict that while, of course, we defend Israel’s right to defend itself and its people against attacks from Hamas, they have to do that in accordance with international humanitarian law, protect civilian lives and, sadly, too many civilians have already lost their lives.”

The Government does not directly supply Israel with weapons, but does grant export licences for British companies to sell arms to the country and can block those sales by suspending the licences.

The UK has taken this course twice before. Margaret Thatcher’s government suspended arms exports following Israel’s 1982 invasion of Lebanon, while Tony Blair’s government blocked sales of some military equipment in 2002.