Live updates: Follow the latest news on Israel-Gaza
Dozens of UK charities have urged MPs to support a ceasefire in Gaza, before a motion in parliament on Wednesday.
The motion tabled by the Scottish National Party is its second to call for an immediate ceasefire in Gaza.
It comes as the Israeli military is threatening to launch a ground offensive in Rafah, the last place of refuge in Gaza where more than half of its 2.3 million population is sheltering.
Amnesty International, Save the Children and Care International are among the 55 organisations to have signed an open letter calling on MPs to support the motion.
“We, along with 71 per cent of the UK public, urge you to support the motion for an immediate and permanent ceasefire to benefit everyone in Israel and Palestine,” the letter said.
The immediate ceasefire was needed to enable “the provision of adequate humanitarian assistance, and the release of hostages, and curtail the risk of regional conflict amid multiple strikes in several countries", it said.
Two British-Jewish organisations, including the Jewish Network for Palestinians, which is supported by Israeli historians Avi Shlaim and Ilan Pappe, and the campaign group Na’amod, are among its signatories.
The death toll and destruction in Gaza was “unfathomable”, the letter said, with almost 30,000 people killed and 11,500 of them children, according to the Palestinian Health Ministry in Gaza.
Latest from the Israel-Gaza war - in pictures
Many of the signatories, including Action Against Hunger, have teams operating in Gaza and the West Bank, and receive first-hand accounts from their staff of the situation there.
Palestinians in Gaza are living in dire conditions, with children at risk of starvation and surgeons operating without anaesthetic, the letter said, telling MPs they “cannot afford to delay any longer".
The letter warned that the humanitarian crisis was “likely to surpass even the horrors we have seen over the last four months".
The UK government must hold Israel accountable for events in Gaza and the West Bank, the letter said.
“Private diplomacy and cautious statements are not enough. Stronger action and accountability needs to be applied,” it said.
The UK government has previously called for a “sustainable ceasefire” in Gaza, adding that this can only be achieved when Hamas no longer controls the territory and the hostages are released.
Foreign Secretary David Cameron has also pressed for immediate humanitarian “pauses” in Gaza, to allow aid to get through.
UK Foreign Secretary calls for sustainable future in region, without militias - video
UK Foreign Secretary calls for sustainable future in region, without militias
The UK launched a $50 million co-funding partnership with Qatar to tackle humanitarian crises around the world, including Gaza, its development minister Andrew Mitchell said on Monday.
But access to aid will not be possible without an end to the war, the letter states.
“This is not possible under bombardment. We need a lasting ceasefire, not ‘pauses’,” it said.
A lasting ceasefire was needed for humanitarian organisations to re-establish their work, and to prevent the loss of life.
“It is imperative that the UK government takes immediate action to support an immediate and permanent ceasefire, for which there is growing international consensus,” the letter said.
