Israel’s actions in Gaza have “bordered on the reckless”, a former head of MI6 has said, amid pressure on the UK government to stop arms sales. Alex Younger, who led the Secret Intelligence Service between 2014 and 2020, said it was “hard not to conclude that insufficient care is being paid to the collateral risks of these operations, one way or another”. He was speaking after the Guardian published a letter from senior lawyers and judges, including three former supreme court justices, warning that the UK government was breaching international law by continuing to arm Israel. Several Conservative MPs have urged Rishi Sunak to stop arming Israel after seven international aid workers, including three British citizens, were killed by an Israeli airstrike in Gaza on Monday. Younger told the Today podcast on BBC Radio 4: “My view is that what happened is essentially systematic of an approach to targeting that has on occasion bordered on the reckless and fundamentally undermines therefore what must be Israel’s political purpose, which is to sustain some moral high ground and some moral purpose.” Mark Lyall Grant, a former national security adviser, said the facts had changed considerably since the government’s lawyers last assessed the situation in Gaza in December. Since then, the international court of justice has suggested in an interim judgment that there is a plausible risk of genocide in Gaza. Last week, the UN security council passed a resolution calling for an immediate ceasefire in Gaza, which Israel has not abided by. A humanitarian crisis has unfolded in the Palestinian territory, with David Cameron, the foreign secretary, accusing Israel of blocking the delivery of aid. “All those developments since then means that if the government lawyers were to look again at this issue they may come to a different judgment,” Lyall Grant told Sky News. “In that case then it would be very difficult for the British government to continue to sell weapons to Israel.” “It’s a question of whether there is a serious risk that the weapons being sold could be used in a breach of international law.” Belgium and Spain have suspended arms exports to Israel. The UK sells comparatively few weapons to Israel but Lyall Grant said that suspending arms sales “would be quite a significant political and symbolic step”. On Wednesday, Labour called for the government to publish the latest advice it had received from its lawyers. David Lammy, the shadow foreign secretary, said UK arms sales to Israel should be suspended if the lawyers had concluded there was a serious risk of breaches of international law. “There is a very clear legal regime in the United Kingdom about arms exports,” said Jonathan Reynolds, the shadow business secretary. “If anything is exported from the UK that could be at risk of being involved in a breach of humanitarian law then it must not be exported,” Reynolds told Sky News. “The right thing to do is to apply that regime and we need to see the advice the government has received.” Suella Braverman, the former home secretary, insisted that Israel was “absolutely not” in breach of international humanitarian law. Braverman, who is on a visit to the country, told BBC Radio 4’s Today programme: “The suggestion itself is absurd and, frankly, an insult to Israel, who have been going above and beyond the necessary requirements to ensure that civilian casualties are limited, to ensure that aid is received on to the Gaza Strip and distributed. “I have seen evidence myself, in terms of very up-to-date photographic evidence, of plentiful food packages and trucks of food, water and medicines getting to the people of Gaza.” The World Central Kitchen charity (WCK) has called for an independent investigation into the Israeli strikes that killed seven members of its team in Gaza on Monday. British victims John Chapman, 57, James “Jim” Henderson, 33, and James Kirby, 47, were among the seven who died in the attack. Guardian Newsroom: Crisis in the Middle East On Tuesday 30 April, 7-8.15pm GMT, join Devika Bhat, Peter Beaumont, Emma Graham-Harrison and Ghaith Abdul-Ahad as they discuss the fast-developing crisis in the Middle East. Book tickets here or at theguardian.live