Husam Zomlot, ambassador of the Palestinian mission to the UK, highlighted the assault on civilians, rescue teams and medical facilities that have happened already.
Mr Sunak reiterated the UK’s support for Israel’s “right to defend itself” on Monday after the Hamas attacks on Israeli soil earlier this month. But in a change of tone, he stressed that this “must be done with respect to international law and international humanitarian law.”
His statement to MPs marked the “beginning of a change” in the UKs position towards Israel, Mr Zomlot said on Tuesday.
“I am really glad. Maybe glad is not the word. I am relieved to see the beginning of a change in the UKs official statements,” the ambassador said.
But those calls should have come earlier, he added. “He should have said that in [the first] second of the conflict.”
Instead the UK’s initial, unequivocal support had given the Israeli government a green light to do “as they wish”, the envoy said.
“The first week the [British] government was off completely off balance. [Their] statements could have been interpreted by the most extreme government as a licence and a green light to simply do as they wish,” he said.
The consequences of this were palpable already, as more than 2,850 Palestinians had been killed in Gaza and the West Bank, among them 1,000 children.
Fifty families had been “wiped off the record”, as no members had survived, Mr Zomlot added.
He stressed that the death toll could be higher, as rescue teams had struggled to collect bodies from the rubble. “Some [rescue teams] have been targeted by Israeli bombardments, when they tried to rescue the victims,” he said.
Palestinians fleeing northern Gaza after a call from Israel to evacuate the area were also targeted “as they tried to leave their homes towards the south”.
Mr Zomlot represents the Palestinian Liberation Organisation (PLO), which formed the Palestinian Authority as the result of the Oslo Accords in 1993. Hamas has administered Gaza since it won elections in 2006, defeating Fatah, the PLO’s largest party. Those elections were not recognised internationally, and Hamas then took control of the Gaza strip by force.
But Hamas’s infiltration of Israel on October 7 and its taking of hostages, could leave the PLO sidelined in any negotiations. Foreign Secretary James Cleverly flew to Israel in the immediate aftermath of the attacks, but has yet to meet his Palestinian counterpart.
PA President Mahmoud Abbas has been meeting with Western leaders to support a solution to the crisis. Mr Abbas spoke with Mr Sunak on the phone on Monday, and is due to meet President Biden on Wednesday, after a meeting with US state secretary Antony Blinken in Amman last week.
Mr Zomlot stressed that the PLO had been actively working to achieve a ceasefire and humanitarian corridors.
“We want to immediately stop the aggression and the atrocities and bombardments. We want the ceasefire and we are working with all our international partners to do so here in the UK,” he said.
He rejected the possibility of a “mass transfer” of civilians to Egypt as some have called for the evacuation of civilians to the neighbouring country.
“We completely reject. We will not allow another round of ethnic cleansing in Palestine,” he said.
He told reporters that he was “constantly” in touch with British government officials, both privately and in public.
“I am in contact with the [British] government constantly. From day one. And we are discussing all these issues, not only in private, but also in public,” he said.
“I have had many meetings with senior ministers, officials, and my colleagues all over the world are doing the same today.”
Mr Zomlot was pictured sitting next to the UK’s Minister of Middle Eastern Affairs Lord Tariq Ahmad at the Bahraini Embassy on Monday, in a meeting about the situation in Gaza and Israel with ambassadors of the Arab League Countries to the United Kingdom.
The Palestinian leadership’s continued commitment to a peace process gave it an active role in the conflict which had “no military solution,” Mr Zomlot added.
But he accused Israel of “undermining” the agreement set out by the Oslo Accords in 2005.
“We committed 30 years ago to recognising Israel, to committing to negotiations and non-violence international resolutions. We remain until this very day committed to these very three principles,” he said.
“But Israel has used these three decades not to set the stage for a two state outcome, but to undermine them.”
Diplomatic possibilities had seen a “lot of traffic” in the last week, and could start shaping solutions for the long term, the envoy said.
“There are a lot of diplomatic efforts [going on] as we speak, right across the world. [There is a] really genuine focus to stop this carnage and stop this madness. Not only to stop, but to also create a different path,” he said.
“This is not the first time we see such images. We want to make sure that we are done with them once and for all."