ACTIVISTS and aid agencies across the world slammed the “calamitous” order by Israel’s military today for more than one million Palestinians to evacuate northern Gaza and head to the southern part of the besieged territory.

The unprecedented order applying to almost half the population comes ahead of an expected ground invasion by Israeli forces of Gaza.

The evacuation order, which includes Gaza City, home to hundreds of thousands of Palestinians, sparked widespread panic among civilians and aid workers already seeking what appears to be non-existent shelter from Israeli air strikes and contending with a total siege that has left them without food, water or fuel.

The UN said the move would affect around 1.1 million people who would be expected to cram together into the southern half of the strip, which is only 25 miles long, even as Israeli air strikes continued to hammer neighbourhoods across the area.

Tel Aviv has said its complete barricade of Gaza would remain in place until some 150 hostages are freed, with Israeli Defence Minister Yoav Gallant vowing to “topple” Hamas and “wipe out” the group’s military capabilities.

It came as campaigners in Britain condemned the government for failing to uphold human rights by supporting Israel’s “ultimatum.”

Defence Secretary Grant Shapps appeared to stop short of explicitly endorsing the evacuation order and related tactics today, and said it is right for Israel to give advanced warning of military action so people “can move.”

“Israel is giving due warning, but they are going after those terrorists, and we absolutely respect Israel’s right to do that,” he told BBC Radio 4’s Today programme.

Mr Shapps was repeatedly asked to explicitly say if Britain supports the evacuation order.

He said “we’ve never been in these times,” and drew a hypothetical comparison to how the government would react if an attack of equivalent scale happened in Britain.

The Tory minister said: “You would expect Britain, and in this case you would expect Israel, to have the right to defend itself.

“Now, if those terrorists then hide themselves within populations, it is right to give that population notice so that they can move.”

Hamas has said Israel’s heavy bombardment of the Gaza Strip has killed 13 hostages, including foreigners, held by the group.

Mr Shapps told ITV’s Good Morning Britain he would treat the claim with “caution” but “deep concern.”

Amnesty International UK chief executive Sacha Deshmukh said it was “extremely worrying” that Mr Shapps was “seemingly unwilling to urge allies in Israel to reconsider this ultimatum.”

He said: “The horrific mass killing of Israeli civilians by Hamas does not absolve the Israeli authorities of their obligations to respect international humanitarian law and to properly protect civilians in their military actions, and all UK politicians should be absolutely clear on this vital principle.”

The Prime Minister told broadcasters at the Joint Expeditionary Force summit in Gotland, Sweden, that “of course Israel should take every possible precaution to protect civilians as they exercise their rightful ability to defend themselves against attacks like this.”

Palestine Solidarity Campaign said in a statement that “all people of conscience will be horrified” by Israel’s evacuation order.

“Palestinians are rightly fearing another Nakba of mass ethnic cleansing,” the statement said, referencing “the catastrophe” of 1948 when thousands were killed or forced to leave their homes when Israel was formed.

“Such a mass evacuation is impossible to organise safely anywhere let alone in a besieged area that has been heavily bombed for a week and where basic infrastructure is collapsing.”

The statement warned that there is “every reason to believe that Israel’s intention is to never allow them to return,” adding: “Israel is seeking to pre-emptively justify the likely mass slaughter of many thousands of civilians, on the basis that they were warned to leave and should do so if they care for their lives.”

The group urged the government and political leaders in Britain to call for an immediate ceasefire and a lifting of the siege on Gaza so that humanitarian aid — including food, fuel, and medical supplies can reach the population.

Foreign turn:

“Forget about food, forget about electricity, forget about fuel. The only concern now is just if you’ll make it, if you’re going to live,” said Nebal Farsakh, a spokesperson for the Palestinian Red Crescent in Gaza City.

Amnesty International’s secretary general Agnes Callamard said the siege put in place by the Israelis was “collective punishment” and amounted to a “war crime.”

She added: “As the occupying power, Israel has a clear obligation under international law to ensure the basic needs of Gaza’s civilian population are met.

UN spokesperson Stephane Dujarric said it would be impossible to stage such an evacuation without “devastating humanitarian consequences.”

He called on Israel to rescind any such orders, saying they could “transform what is already a tragedy into a calamitous situation.”

Hamas, meanwhile, called on Palestinians to stay in their homes, saying Israel “is trying to create confusion among citizens and harm the cohesion of our internal front.”

It urged Palestinians to ignore what it said was “psychological warfare.”

Gaza’s Health Ministry said it was not possible to evacuate the many wounded from hospitals and hospital staff would not heed the warning.

“We cannot evacuate hospitals and leave the wounded and sick to die,” spokesperson Ashraf al-Qidra said.

In the event of severe Israeli strikes, he said there was simply no other place in the Gaza Strip to take and treat patients.

The UN agency for Palestinian refugees, known as UNRWA, also said it would not evacuate its schools, where hundreds of thousands have been forced to take shelter.

Pressed by reporters on whether the army would protect hospitals, UN shelters and other civilian locations, an Israeli military spokesperson, warned that “it’s a war zone.”

He added: “If Hamas prevents residents from evacuating, the responsibility lies with them.”

Clive Baldwin, a senior legal adviser at the New York-based Human Rights Watch, said “ordering a million people in Gaza to evacuate, when there’s no safe place to go, is not an effective warning.

“World leaders should speak up now before it is too late.”

Jan Egeland, the secretary general of the Norwegian Refugee Council called the order by the Israelis to evacuate “a violation of international law.”

General director of Medicine Sans Frontier Meinie Nicolai said the move by the Israelis represents an attack on medical care and on humanity.

She said: “‘Unprecedented’ doesn’t even cover the medical humanitarian impact of this. Gaza is being flattened, thousands of people are dying, this must stop now. We condemn Israel’s demand in the strongest possible terms.

Hanan Ashrawi, the former Palestinian peace negotiator, said this wasn’t an “evacuation” by the Israelis but a “forced expulsion.”

She added: “Most Gazans are 1948 refugees who were terrorised and expelled in the Nakba. The best place for them to go is to their original homes and lands — that should solve Israel’s problem with Gaza.

The war has already claimed over 2,800 lives on both sides and sent tensions soaring across the region. Israel has traded fire in recent days with Lebanon’s Hezbollah militant group, sparking fears of an ever wider conflict, though that frontier is currently calm.