Jeremy Corbyn and four other independent pro-Palestine MPs have written to the foreign secretary falsely claiming that the International Court of Justice said Israel could be accused of a “plausible genocide”, even though the ICC president has explicitly debunked “what’s often said in the media”.

They also described a speculative letter published in the Lancet, which arbitrarily multiplied the death toll in Gaza, as a “study”.

The five parliamentarians are demanding that the government immediately suspend all weapons sales to Israel, drop any legal challenge preventing the ICC from issuing a war crimes warrant against Benjamin Netanyahu, and recognise the state of Palestine.

The letter, signed by Corbyn, Adnan Hussain, Ayoub Khan, Iqbal Mohamed, and Shockat Adam, states: “We… have been elected by our representative constituents, in part, to represent their concerns regarding the ongoing catastrophic situation in Gaza, which has been described by the [ICJ] as a ‘plausible genocide’.”

Speaking on the BBC in April, however, the former president of the court said the ICJ had issued no such verdict.

“I’m glad I have a chance to address that because the court’s test for deciding whether to impose measures uses the idea of plausibility. But the test is the plausibility of the rights that are asserted by the applicant, in this case South Africa” Joan Donoghue said.

“The court decided that the Palestinians had a plausible right to be protected from genocide and that South Africa had the right to present that claim in the court.

“It then looked at the facts as well. But it did not decide – and this is something where I’m correcting what’s often said in the media – it didn’t decide that the claim of genocide was plausible.”

The letter published by the pro-Palestine MPs continued: “There is no doubt you will be aware the situation in Gaza worsens moment by moment. The urgency for action cannot be understated…

"Gaza’s Ministry of Health holds the death toll since October at 38,000. However, a study published in the journal, The Lancet, estimates that even a conservative measure of the death toll in Gaza could exceed 186,000.

"The study points out that the offical toll does not take into account the thousands of people buried under the rubble, nor the indirect deaths caused by the destruction of health facilities, food distribution systems and the break down of other public infastructure.”

The text published in The Lancet, however, was not a study but a letter, which was not peer-reviewed.

This figure was created by multiplying the current death toll, as reported by the Gaza’s Hamas-run health ministry, by five.

The estimate does not suggest that 186,000 have been killed in the nine months of war so far.

The letter to David Lammy continues with a series of demands of the new foreign secretary.

These include calls for the resumption of Britain’s funding of the Palestinian refugee agency UNRWA and support for humanitarian aid flows in Gaza, the UK to use its position on the UN Security Council to demand a ceasefire, and the issuance of a statement supporting the ICJ’s actions.

The MPs also call for Lammy to act to secure the release of all remaining Israeli hostages, to advocate for the deployment of a United Nations peacekeeping force to Gaza, and the sanctions to be imposed on individuals advocating for the genocide of Palestinians.

The letter states: “We urge you to implement these actions as crucial steps towards the alleviation of a catastrophic situation in Gaza, and fulfil the obligations of the United Kingdom in international law.”