The US Middle East envoy Steve Witkoff has praised the “incredible input and tireless efforts” of the UK’s National Security Adviser Jonathan Powell in bringing about the ceasefire in Gaza.

In a social media post, Witkoff also said he wanted to “acknowledge the vital role of the UK in assisting and coordinating efforts that have led us to this historic day in Israel”.

The comments sharply contrast with those of Mike Huckabee, the US’s ambassador in Israel, who said a UK minister was “delusional” for suggesting the UK played a “key role” in the process.

The specific and personal praise for Powell from Witkoff is a boost to the national security adviser at a moment of political vulnerability.

Powell is facing pressure over what role he played in the collapsed court case against two men accused of spying for China.

Sources in government had for some time been emphasising the strength of the relationship between Powell and Witkoff.

The two men are said to be in almost daily contact. Their relationship has become closer through their work on the conflict between Russia and Ukraine, with Powell playing an instrumental role in trying to rebuild the US-Ukraine relationship after President Trump and President Zelensky’s public confrontation in the Oval Office in February.

Powell was also in Egypt last week as negotiations over the ceasefire were being finalised.

Some in government expect Powell’s experience of negotiating the Good Friday Agreement in Northern Ireland will be called upon by the US and others in the coming weeks and months, especially on the issue of decommissioning of weapons.

On Sunday, Education Secretary Bridget Phillipson told Sky News the UK had “played a key role behind the scenes” in shaping the Gaza peace plan and had been involved in “complex matters of diplomacy”.

Responding on the social media platform X, Huckabee said: “I assure you she’s delusional. She can thank Donald Trump anytime just to set the record straight.”

Israel’s deputy foreign minister Sharren Haskel added to Huckabee’s criticism arguing that the UK’s decision to recognise Palestinian statehood had “actually pushed Hamas to embolden their position”.

However, on Monday, Witkoff publicly lauded the UK’s involvement and specifically the role of Jonathan Powell.

Asked about his praise, Conservative leader Kemi Badenoch said: “I was not born yesterday.

“I think it is actually very sad that the government is having to beg people to send tweets to say something nice about Jonathan Powell.

“I think that that is quite tragic, the way that the UK’s reputation is falling under this Labour government.”

Sir Keir Starmer has travelled to Egypt, where US President Donald Trump and negotiators from Egypt, Qatar and Turkey will sign the peace plan.

Palestinian President Mahmoud Abbas is also expected to attend the international summit in Sharm el-Sheikh, along with world leaders from around 20 countries.

The ceasefire brokered by Trump in Gaza began on Friday morning after Israel and Hamas agreed to the first phase of the peace plan.

The last 20 of the Israeli hostages have been released and are now back in Israel, and Hamas is due to hand over the remains of up to 28 deceased hostages.

Israel is releasing 250 Palestinian prisoners and 1,700 detainees from Gaza, while increased amounts of aid should enter the Gaza Strip.

Sir Keir Starmer appointed Powell as his national security adviser in November last year, taking over from Sir Tim Barrow.

The holder of the post is always appointed by the prime minister but is normally a civil servant. Powell, in contrast, is a special adviser – a political appointee whose wages are paid by taxpayers.

Powell was instrumental in brokering the 1998 peace deal in Northern Ireland when he was chief of staff to then Prime Minister Tony Blair.

He left Downing Street after 10 years and went on to set up Inter-mediate, a conflict resolution charity which has helped negotiate peace agreements in Colombia, Mozambique and Spain.

Bronwen Maddox, director of the international relations think tank Chatham House told BBC Radio 4’s Profile that Powell made the case that to achieve peace people had to talk to their enemies “even if they have blood on their hands”.

Talking previously about the process of negotiation, Powell has said: “It’s much harder to kill people when you know them.

“You have to get to know people and build a relationship of trust to break out of the cycle of violence.”