Now is the most perilous moment May has yet faced

The sudden resignation of David Davis, who has been leading the Brussels negotiations, only 48 hours after the Chequers meeting, explodes at a stroke the Government’s pretence that all is sweetness and light.

This trains the spotlight relentlessly on the Prime Minister. Can she survive this massive blow to her authority, let alone control this unruly and fractious Cabinet?

Michael Gove’s boast that there is total unity is now laughable.

The first indication that all was not well was the carefully-leaked crude gutter language used by the Foreign Secretary Boris Johnson about the new “way forward”.

Davis’ resignation, and his biting resignation letter, will give more power to Brussels and less to Westminster as this shaky Government battles on, weakened beyond measure. Labour now believe, as do others, that the Government is falling apart.

This is the leakiest, most quarrelsome and fractious Cabinet I can remember. The Prime Minister’s done her level best to bring the warring parties together, but their differences are now so deeply entrenched, as shown by Davis’ departure, that harmony is surely nowhere in sight.

The Prime Minister now faces the most perilous moment of her political career.

• Why was the telephone number of a local minicab firm made available to Cabinet ministers attending the crucial Chequers Brexit talks on Friday?

The answer is simple. Should any of the disgruntled ministers, dissatisfied with the Prime Minister’s new Brexit blueprint, have stormed out of the meeting in disgust, they would have received a shock as they exited the front door. Because, the moment they chose to detach themselves from the Cabinet, their ministerial car would have been unavailable to them.

That would have entailed a tedious walk the length of the seemingly endless drive from the mansion to the exit gates. You could say the Prime Minister had a captive audience.

• Has the House of Commons lost its bottle? There appear plenty of good reasons why the Speaker, John Bercow, should be invited to leave the chair and thus make way for somebody new.

Yet despite the groundswell of dissatisaction against Bercow – amounting in some cases to animosity – no serious attempt has been made to shift him. He promised to serve for nine years – that period has now passed, and nothing has happened (a broken pledge?).

He breached his traditional duty of total impartiality, for instance by announcing – without actually consulting the House of Lords – that President Trump would not be allowed to address both Houses in the Palace of Westminster; a very real snub and totally out of order for a Speaker. He has worn lapel badges expressing support for campaigns he approves of.

The Commons Speaker has to learn to be totally neutral – and this is not happening.

He refuses to wear the traditional robes the Speaker has worn down the centuries, and he interrupts far too much, often spoiling the flow of debate.

On the credit side, he has allowed far more urgent questions than his predecessors – a fact which appeals to many back-benchers.

Yet overall, the view is that he should go, enough is enough. But there are no signs that this will ever happen.

• Sadiq Khan, Mayor of London, is not only a disgrace to the capital but a damaging embarrassment to the UK as a whole. His crass decision to allow the anti-Trump lobby to fly a grotesque balloon over London, depicting Trump as a baby in a nappy, was stupid and infantile.

You may not appove of President Trump, but he is, nevertheless, the elected leader of the United States, which is the UK’s greatest ally and with whom we share a special relationship.

No wonder Trump is barely visiting London during this short trip.