'Is she off to a Bananarama gig?' Viewers are distracted by Andrea Leadsom's 'Pink Ladies' leather jacket during dramatic Brexit vote

By Jack Doyle 

What happened yesterday?

The Government lost three votes in a day, the first time that has happened since 1996 – an ominous date for the Tory Party which went on to face catastrophic electoral defeat the following year. The first two were on the Brexit legal advice given to Cabinet by Attorney General Geoffrey Cox.

They were damaging, but not disastrous. The third, which is potentially much more significant, was on an amendment, proposed by leading Remainer Tory rebel Dominic Grieve, setting out what could happen if Theresa May's deal is voted down next week. It could, in theory, give MPs vast leverage over the next steps on Brexit.

Why is the legal advice vote significant?

Last month the Commons demanded the full legal advice be published. Ministers refused. Yesterday MPs voted to declare this decision a contempt of Parliament – a serious form of legal admonishment.

To avoid the prospect of ministers being suspended by the House, the Government rolled over and agreed to release the document today. No 10 fought tooth and nail to resist publishing, warning to do so would be 'against the national interest' and breach historic conventions. To placate MPs, Mr Cox made a statement to Parliament describing what it said and published a summary.

Much of the document will be familiar, but it will make plain the gravity of Mr Cox's warnings about the UK being trapped in the Northern Ireland backstop, potentially hardening opposition to the deal among rebel Tory MPs.

What does the Grieve amendment mean?

Following an earlier row this summer, Mr Grieve won a concession that if the deal falls, the Government will have to come back to the Commons within three weeks to set out what course it will then take.

As a result of yesterday's vote, MPs will now be able to propose what alternative course of action the Government should take by making amendments to the motion and voting on them.

Almost inevitably, the likely proposals will include the UK staying in a permanent customs union, or membership of the single market, or both – or a second referendum.

For its supporters, this makes 'no deal' impossible as the Commons – which is overwhelmingly opposed to crashing out – would immediately make clear its disapproval. Some hardline Brexiteers deny this, arguing that any amendment would not be legally binding on the Prime Minister. In theory this is true, but any such vote would heap huge political pressure on the Government to comply.

Where does this all leave us?

With nearly 100 MPs publicly expressing their doubts about the deal, its chances of passing on Tuesday already appeared slim. Losing a string of votes exposes just how weak Mrs May's grip on a fractious and volatile Parliament has become. With this in mind, the Grieve amendment could be hugely significant.

If it is seen to reduce the chances of a no-deal Brexit, could it yet convince hardline Eurosceptic rebels they should back Mrs May's deal?

Or will they press on, with the danger that the future of Brexit falls into the hands of a Remain-dominated Parliament which is flexing its muscles more every day and could yet find a way to sink Brexit altogether?