The Foreign Secretary said Britain expected Israel to “adhere to international humanitarian law” as the war enters its seventh month.
Foreign Secretary David Cameron said in a newspaper column that Britain's aid to Israel was dependent on compliance with international humanitarian law.
The former prime minister's comments came just days after an Israeli airstrike killed seven aid workers, including three British nationals, in the Gaza Strip.
“Our support is not unconditional,” Cameron wrote in Sunday's Sunday Times. “We expect such proud and successful democracies to abide by international humanitarian law, even when challenged.”
The British government has been a staunch ally of Israel since Hamas attacked southern Israel on October 7.
But Prime Minister David Cameron has hardened his words in recent months, citing the dire humanitarian situation in the Palestinian enclaves.
Earlier on Sunday, the prime minister warned that “the prospect of starvation is real” in Gaza as Royal Navy ships head to the Mediterranean to help set up a maritime aid corridor.
Prime Minister Cameron said the UK was working with the US, Cyprus and others to set up “a new temporary pier off the coast of Gaza to get help as quickly and safely as possible”.
“I was shocked by the bloodshed.”
Meanwhile, in a statement on Sunday marking six months since Hamas' first attack, British Prime Minister Rishi Sunak reiterated his call for Palestinian groups to release Israeli prisoners and immediately stop fighting.
“We continue to support Israel's right to defeat the terrorist threat of Hamas… But the whole of Britain is shocked by the bloodshed and the killing of Britain's brave heroes delivering food to people in need. I'm appalled,” he said.
Mr Sunak is under increasing political pressure to end arms sales to Israel after an Israeli airstrike on Gaza killed seven aid workers, including three British nationals.
Several of Israel's main allies also expressed outrage at the death toll and called for an independent investigation into the attack.
Australian Prime Minister Anthony Albanese said he spoke to Netanyahu and told him his country was “outraged” by the death of Australian aid worker Zoumi Francomme.
legal challenge
The UK government is also under pressure to publish updated legal advice on Israel's conduct of war in Gaza, which could affect UK arms exports.
Last week, three former Supreme Court justices joined more than 600 British legal professionals to call on the government to halt arms sales to Israel, saying Britain could be complicit in genocide in the Gaza Strip.
Britain supplied Israel with 42 million pounds ($53 million) worth of weapons in 2022. In December, the government decided that these exports should continue, but that review would continue.
Prime Minister David Cameron said on March 8 that a new judgment in this regard was underway and would be expected “in the coming days”.
A poll published in the Guardian found that a majority of British people support a ban on arms sales to Israel. According to the poll, 56% of people support the ban, while 17% oppose it.