THERESA May withstood a mixture of emotions last night as Angela Merkel welcomed “progress” on Brexit while Donald Trump claimed Britain was in “turmoil” and he would find it easier talking to Vladimir Putin than her.

As the Prime Minister prepares to publish her White Paper tomorrow, giving more details of her Chequers Plan for a softer Brexit, she received some positive reactions from senior European figures.

The German Chancellor told a press conference at the Western Balkans summit in London that the EU27 would present its response to Mrs May’s compromise plan in due course and added: "We are looking forward to interesting discussions but we will also have these inspired by the spirit of friendship and the wish to have good relations in the future."

Earlier, Michel Barnier, the EU’s chief negotiator, appeared upbeat when he said he was looking forward to a “constructive discussion” on the White Paper, noting how “after 12 months of negotiations we have agreed on 80 per cent of the negotiations,” adding that he was determined to reach agreement on the remaining 20 per cent by November.

In Dublin, Leo Varadkar, the Taoiseach, was equally positive, telling the Irish Parliament: “If the United Kingdom was able to relax some of its red lines, then the European Union could be flexible too. We are now entering into that space.”

But a contrasting sour note was sounded by the US President, who was asked about his journey to Europe for Nato talks today, his four-day visit to Britain, starting tomorrow, and his summit with the Russian President in Helsinki on Monday.

Mr Trump told reporters: "So I have Nato, I have the UK, which is in somewhat turmoil, and I have Putin. Frankly, Putin may be the easiest of all."

Asked whether Mrs May should be replaced as PM, he replied: "Well that's up to the people. I get along with her very well, I have a very good relationship. That's certainly up to the people, not up to me."

The President said he had not spoken with Mrs May and then added: "Boris Johnson is a friend of mine. He's been very, very nice to me, very supportive. Maybe I'll speak to him when I get over there."

When she was asked about Mr Trump's remarks, the PM said: “I'm looking forward to seeing President Trump not only at the Nato summit coming up in the next couple of days but also, obviously, when he comes to the United Kingdom at the end of the week.

"There's much for us to discuss. As you know, the special relationship we have with the United States is our longest and deepest defence and security relationship, so we will be talking about those issues but also talking about trade issues,” she added.

Earlier, Mrs May chaired the first meeting of her new-look Cabinet, when she paid tribute to Boris Johnson and David Davis, following their resignations, and welcomed the new and promoted members, including Dominic Raab, the Brexit Secretary. Colleagues banged the Cabinet table in the traditional sign of approval.

In a tweet clearly designed to show she was not being knocked off course, the PM said: "Productive Cabinet meeting this morning - looking ahead to a busy week. And sending our best wishes to @England for tomorrow!"

But while Mrs May sought to present a positive front and colleagues rallied round her – Michael Gove, the Environment Secretary, declared he was “100 per cent” behind her Chequers Plan – two developments showed how the potential threat to her premiership remained.

Ben Bradley and Maria Caulfield resigned their posts as Vice-Chairmen of the Tory Party in protest at the PM's strategy.

Mr Bradley, the MP for Mansfield, said it would “damage the UK’s opportunities to develop global trade and be "an outward-looking nation in control of our own destiny" following Brexit.

Ms Caulfield, the MP for Lewes, in her resignation letter to Mrs May said the Chequers Plan would “not fully embrace the opportunities that Brexit can provide.”

She warned: "The policy may assuage vested interests but the voters will find out and their representatives will be found out. This policy will be bad for our country and bad for the party. The direct consequences of that will be Prime Minister Corbyn."

It was suggested that the Brexiteer rebels would seek to keep up the pressure on their party leader by announcing a resignation every day until the start of the late July summer recess.

In contrast, leading pro-EU Tories signalled their support for the PM's compromise proposal, describing it as a "welcome dose of reality".

Remainers Antoinette Sandbach and Stephen Hammond gave their backing to the Chequers Plan.

The former, who represents Eddisbury in Cheshire, said it was a “concrete plan,” which she supported while the latter, who represents Wimbledon, described it as a “sensible proposal," which aimed to “remove the need for tariffs, customs checks and controls".