The mother of parliaments is braced for the mother of days on 19 October

There have been a lot of turbulent days in Westminster over the past few years, but Saturday 19 October is shaping up to be a “perfect storm” for Brexit.

Normally, of course, Westminster would be in a state of calm on a Saturday, and it is a mark of the scale of the impending tempest that MPs are being called to sit at the weekend at all.

Such an event has only ever happened before at times of major emergency – the outbreak of the Second World War, the Suez crisis and the invasion of the Falklands (as well as that time in 1949 when MPs decided to give up a Saturday to finish off their business so they could go off for their summer holidays early…).

The exact state of the political weather will be set by the Brussels summit on Thursday and Friday. Agreement on a Brexit deal – currently looking all but impossible – would provide Boris Johnson with a fair wind to sail home to a hero’s welcome from the Tory benches.

Far more likely is that he will return empty-handed to face a whirlwind of rage and accusations from all sides of the house, buffeted by Brexiteer demands to sail into the perilous and uncharted waters of no deal at the end of the month, and by calls from the opposition to accept the temporary haven of an extension to Article 50 negotiations to January or June.

The PM may deploy the lightning strike of a vote to confirm 31 October as the date of Brexit, to force MPs to nail their colours to the mast ahead of an expected general election – and to attempt to ensure that they take the blame if he gives in to the pressure for delay.

He could make another bid to trigger an election under fixed-term parliament legislation to test the resolve of opposition parties who say they will not go to the country until no deal is averted.

But the “Remain alliance” may have thunderbolts of their own, in the shape of a motion to seize control of the agenda and force what they believe could be a successful vote on a second referendum.

Meanwhile, outside Buckingham Palace, the dark storm clouds will be rolling in, in the shape of a People’s Vote march potentially sweeping more than a million people through the streets of the capital to the doors of parliament under the banner Together for the Final Say.

And the final thunderclap could come from the courts.

The prime minister has suggested he will tie himself to the mast and block his ears to the legal and political voices demanding he meet that day’s deadline to sign a letter requesting a Brexit extension.

But if he does so, he could find his ship sunk by the power of the judges to appoint someone else to do it – or even the ultimate tsunami of an order from the Queen to remove him from office.

It is difficult to say just what will be left standing when the day’s gales have abated, and whether the course will be set for no deal, a referendum, an election or just more delay. There is little doubt, however, that the storms of 19 October will reshape the political landscape like few other days in our recent history.

Yours,

Andrew Woodcock

Political editor