Israel’s renewed offensive and three-month siege of the Gaza strip has attracted mounting criticism, leading to sterner rhetoric from European leaders, even from key allies.

British Prime Minister Keir Starmer, and German chancellor Friedrich Merz are among those denouncing Israel's latest offensive, marking a change in direction from their earlier support of the war.

On Wednesday, the UK called for an immediate independent investigation into the killings at the aid distribution centre and for the perpetrators to be held to account. Dozens of people have been killed in recent days as they tried to gain access to food.

Middle East Minister Hamish Falconer said: “Civilians who have endured 20 months of war should never face the risk of death or injury to simply feed themselves and their families.

“Israel's unjustified block of aid into Gaza needs to end. It is inhumane,” he said, adding that the country should allow the UN to deliver aid “at scale to save lives”.

But experts warn the tougher tone needs to match policy decision, ahead of the UN peace conference at the end of the month.

“It’s time for the rhetoric to be turned into action. It’s time to end the war and have a very clear eyed path to stability,” said Nomi Bar Yaacov, an international peace negotiator at the Geneva Centre for Middle East Policy.

"It is clear that Israel’s behaviour in Gaza and the West Bank has alienated its traditional friends, including Germany, the Netherlands and the UK. What is needed is action more than words," said former British diplomat Sir Vincent Fean, who served as Consul General to Jerusalem.

Mr Starmer described the situation in Gaza as “intolerable” in parliament on Wednesday, reiterating comments made at press conference in Scotland on Monday. He said Gaza was facing “dark days”.

Speaking in Parliament, he described the Israeli government’s conduct in the 25 mile-long strip as “counterproductive and intolerable”.

He said: “We will keep looking at further action along with our allies, including sanctions, but let me be absolutely clear: we need to get back to a ceasefire.

“We need the hostages who’ve been held for a very long time to be released, and we desperately need more aid at speed and at volume into Gaza, because it’s an appalling and intolerable situation.”

The UK suspended new trade talks with Israel and imposed new sanctions on Jewish settlers in the West Bank last month, using its harshest language yet.

Yet the UK government has not yet given signs that it will recognise the Palestinian state soon, and is rejecting calls to impose a total arms embargo on Israel.

Suggestions that the UK was considering sanctions against far-right cabinet Ministers Itamar Ben Gvir and Bezalel Smotrich have not materialised. Mr Starmer included Palestinian statehood recognition in his party’s election manifesto, but stressed this would only happen as “part of a peace process”.

Mr Fean said the "serious shift" in UK policy was "encouraging" – and that the UK should work with France on a coalition that would lead to Palestinian statehood recognition at the UN conference this month.

"The Prime Minister is working closely with President Macron on several fronts: Ukraine, rapprochement with the EU and Israel-Palestine.

"The New York conference matters a lot. I would like to see the UK, with its historical responsibilities working with France to recognise Palestine unconditionally in New York.

"If the UK and France act together, others will follow for example Canada, Australia, Belgium, Luxembourg," he said.

Germany has been Israel’s strongest ally in Europe, and says it has a historical duty to stand with Israel owing to the Holocaust.

Yet last week Chancellor Friedrich Merz said he “no longer understands” what the war’s objectives are. "It's a human tragedy and political catastrophe," he said last week in an interview. "Frankly speaking, I no longer understand what the goal of the Israeli army in Gaza Strip is.

"When lines are crossed, when international humanitarian law is truly being violated, the German chancellor must say something about it," he stressed.

Foreign Minister Johann Wadephul described Israel’s blockade of Gaza as “unacceptable”, and said later in the week that they were reviewing future arms sales to Israel.

Berlin would assess whether Israel’s actions in Gaza were “compatible with international humanitarian law”. “We are examining it, and based on this review, we will approve further arms deliveries if necessary," Mr Wadephul said in an interview with Sueddeutsche Zeitung.

French President Emmanuel Macron has led, with Saudi Arabia, the creation of a UN peace conference this month, and is pushing for western countries to recognise a Palestinian state.

Last week, Mr Macron asserted that recognition was “not only a moral duty but a political necessity”.

The Israeli foreign ministry accused Mr Macron of a continuing “crusade against the Jewish state.” “The facts do not interest Macron. There is no humanitarian blockade. that is a blatant lie,” the Ministry said in a social media post.

Despite the growing rift between Israel and France, Mr Fean said that the UN conference will be key in developing a road map. "We need a plan that produces an outcome that is credible in terms of mutual security and self determination for two peoples."

Ms Bar Yaacov urged European leaders to look at existing transitional plans for Gaza as they formulate a framework towards long-term peace.

"The plan for a postwar Palestinian transitional technocratic government in Gaza are well known to all those engaged in trying to resolve the conflict. They've been agreed to by Hamas, all of the Palestinian factions," she said.

The European Union may also suspend parts of its trade agreement with Israel when it concludes its review this month about whether or not Israel may have broken international law in Gaza.

In May, 17 member states backed a Dutch proposal to formally review the agreement, over its compliance with article 2, which requires it to “respect human rights.”

The European Commission’s chief, Ursula von der Leyen, who gave the EU’s blanket support for Israel after the October 7 Hamas attacks, said for the first time last week that Israel’s “abhorrent” killing of civilians “cannot be justified under humanitarian and international law.

Mr Fean said this could lead to the "selective suspension of Israel from elements of the agreement such as the R&D co-operation programme."

The outliers now are Hungary and the Czech Republic, who were among the few handful of states to vote against the review.