A week that began with one late night bombshell for Theresa May has ended with another. Five days ago it was David Davis’s resignation, now Donald Trump’s Brexit blast in the Sun.

This week was always going to be a potential week from hell for the Prime Minister: trying to sell her Chequers plan to her mutinous backbenchers and attempting to avoid a Brexit row with the volatile US President during his controversial UK visit. But the week has gone even worse than she feared. It has been her worst week since her last worse week. Both her aims have ended in disastrous failure: two Cabinet resignations, the growing threat of a leadership challenge and now trashed by Trump.

At Westminster, as if the resignations of David Davis and Boris Johnson weren’t unsettling enough, opposition to the Chequers deal and the Brexit white paper among Tory MPs appears to be growing by the day. And then even before their joint news conference after their Chequers talks and a lunch of Dover sole, Chiltern lamb and lemon meringue, the President managed to undermine the PM not once, not twice but three times with outspoken remarks about Brexit, Vladimir Putin and Boris Johnson.

First, speaking to reporters on the White House lawn before he left Washington for Nato, his UK visit and his Helsinki summit with Vladimir Putin, he said the UK was in “turmoil”, that meeting Putin would be “easiest” and that he might speak to Boris Johnson during his visit.

Second, at his Nato news conference in Brussels, he described Britain as a “hot spot right now with a lot of resignations” and questioned whether Theresa May’s Brexit policy was what voters wanted when they backed Leave in 2016.

But, like the Dover sole on the Chequers lunch menu, that was just for starters. Third, in his explosive Sun interview, published at 11pm - barely an hour after Theresa May pleaded with him in her Blenheim banquet speech for a post-Brexit trade deal - he said her Brexit blueprint would “kill” hopes of any future trade deal with the US.

And in a wounding personal attack that will be seized on by hardline Brexiteer Tory MPs, he attacked the PM’s negotiating strategy before declaring that Boris Johnson would be “a great Prime Minister”.

So who has been briefing the President? On the BBC’s This Week Andrew Neil asked Donald Trump’s friend Nigel Farage: “Have you been winding him up on Brexit?” “We’ve had the odd chat about it,” Farage replied, smirking.

So much has happened this week that the resignations of David Davis and Boris Johnson seem like a long time ago now. In fact they were only a few days ago.

David Davis claims he tried to minimise the damage to the Prime Minister of his resignation by announcing it late on Sunday night, missing the first editions of the newspapers and the main TV news bulletins. Well, up to a point, David. The later editions quickly caught up. The Times’ deputy political editor, Sam Coates, told me he didn’t leave work until 1.30am on Monday morning.

My Sky News colleague Lewis Goodall, who had just left work at our Westminster bureau when the Davis resignation broke just before midnight, had worse luck. After returning to work and playing a blinder with numerous live broadcasts in the early hours and putting together a comprehensive VT for our Sunrise programme, he got locked in the gents toilet after answering a call of nature, because the electronic locking devices kick in at midnight and you need your pass to get out, and he had to leave via the fire escape!

Why did David Davis quit? The weekend before his resignation I had a longish chat with him as we sipped bubbly under a marquee in north London’s leafy suburbs at the 50th birthday party of a Brexit-supporting broadcaster.

He sounded weary and worn out by the exhausting Brexit process. He said he was due to spend Sunday reading the latest draft of the white paper, which he said was the ninth. Yes, reading it, not writing it, he said, which underlines the extent to which he had been sidelined in the whole process. But, to be fair, at no point did he say anything critical or derogatory about the Prime Minister to me.

By Monday lunchtime, though, David Davis’s late night resignation had already been overshadowed by the latest Boris Johnson pantomime. I was at The Crystal, a fancy glass conference venue close to the City Airport in East London, where the foreign secretary - as he still was at lunchtime - was due to chair the Western Balkans Summit and host a 5pm news conference.

At midday his deputy, the always affable Sir Alan Duncan, told journalists Boris would be late, because he had to attend a Cobra meeting in Whitehall on the novichok poisonings and the death of Dawn Sturgeon. Fair enough, we all thought. But it soon emerged that not only was Boris not at the Cobra meeting, but that he was holed up in his official residence, 1 Carlton Gardens. At that point, one of Craig’s laws of politics kicked in: when a Cabinet minister who’s tipped to quit starts pulling out of important meetings their resignation is imminent.

As others have observed, Monday was the first time two Cabinet ministers had quit in 24 hours since Lord Carrington - who died this week - and Humphrey Atkins resigned over blunders leading up to the Argentine invasion of the Falklands in 1982 (the year I became a political correspondent!). And as others have also remarked, at least that was a real war, as opposed to a Tory civil war.

Their resignations were co-ordinated. Were those of David Davis and Boris Johnson? I asked a minister at the heart of the Brexit process. “Not judging by their relationship over the past year,” I was told. And the minister also told me that Chequers last Friday evening it was Boris Johnson, no less, who toasted the Prime Minister after the Cabinet agreed the deal!

Pantomime turned to farce when the new Brexit Secretary, Dominic Raab, looking like a frightened rabbit caught in the glare of car headlights, endured a baptism of fire as he presented the white paper to MPs in a Commons statement. I can’t recall a time when the Speaker suspended the sitting for five minutes after MPs brought copies of a white paper in boxes into the chamber and started handing them out to colleagues who’d had no advance sight of them.

Never mind, Prime Minister. Next week can’t possibly be as bad as this worst week since the last worst week, can it? What’s that? Some Tory Brexiteers are threatening to vote with Labour in the Commons against third reading of the trade bill, potentially killing a key piece of Brexit legislation? So that means the Prime Minister could face a choice of fight and maybe lose or pull the vote?

Perhaps she should ask Donald Trump for advice. After all, he seems to have plenty to offer on Brexit. On second thoughts, maybe not.

Jon Craig is chief political correspondent at Sky News.