Theresa May is in her Berkshire constituency today, preparing to formally step down as Tory leader later.

And last night’s Peterborough by-election result, together with the European elections disaster, proves just why she’s going. If the PM had somehow doggedly refused to resign by now, coming third in a traditional Labour-Tory seat would have sealed her fate.

For Nigel Farage, it was a case of ‘close, but no cigar’. Labour’s Lisa Forbes beat the Brexit Party’s Mike Greene by 10,484 votes (31%) to 9,801 (29%) – a majority of just 683. The Tories trailed a distant third with just 21% of the vote, while the Lib Dems quadrupled their support to grab 12%.

For Farage, it confirms just why he was right to bottle it and not stand himself in the seat (just imagine failing to get into the Commons an EIGHTH time). He was right to point out that by-elections depend on data (to identify and target supporters) and his party had very little of it.

But as with his previous moans about losing by-elections because rivals had a better postal vote operation, it just exposes that Farage is not running a political party, he’s the head of a massive pressure group.

Add in the lack of any domestic policy and you can see why a general election would be a major problem for him. If the Brexit party can’t win a by-election, how on earth can it  cope in a first-past-the-post national election when its resources will be spread thinly?

Labour’s superior local knowledge and focus on austerity, boosted by a huge get-out-the-vote operation, certainly helped mobilise their core vote.

A flood of Momentum activists from across the country helped ensure 500 Labour members were knocking on doors on polling day itself. One local activist was in tears yesterday, saying she “couldn’t believe this many people would ever come to Peterborough”.

For the Tories, its collapse in vote share shows how Brexit is tearing their base apart. Some of their supporters flirted with Farage, some stayed at home and some may have switched to Labour on austerity.

But many will also see that Remainer moderate Conservatives defected to the Lib Dems. That’s why the Tory leadership contenders have a real difficulty interpreting this result as a clear-cut warning that they need to tack closer to the no-deal nirvana that Farage espouses.

As for Labour, the battle now begins over what Peterborough tells us about the party’s Brexit policy. Some second referendum sceptics in the shadow cabinet will see the result as a vindication of Corbyn’s fence-sitting to date.

They will argue that if there had indeed been a single ‘Remain’ candidate put up by the LibDems/CHUK/Greens, they would have taken votes from Labour and enabled an historic Farage victory.

Yet it was telling that shadow transport secretary and Corbyn loyalist Andy McDonald was the MP picked to deliver the leadership’s message on the Today programme. And he said two interesting things. First this: “Any deal that would come through Parliament should go back to the people, we should have a second vote”.

But McDonald also said this: “We are looking down the barrel of a no-deal…If that’s the choice we’ve got to go back to the people and say the choice is no-deal or the one that we’ve got now.”

That felt like he was backing a referendum with just two options on it: no-deal and Remain. Labour’s ‘jobs-first Brexit’ sounded as broken as May’s ‘compromise Brexit’. There was an important Twitter thread yesterday from radical Leftist Ash Sarkar setting out why Corbyn’s current strategy won’t survive the party conference in September.

Yes, the Peterborough result could panic the Tories into going for Boris Johnson as the best candidate to out-Farage Farage. But in choosing a no-dealer, the Conservatives may well gift Corbyn the second referendum/Reform-and-Remain position so many of his members and supporters want.

It’s been on life-support for years, but a ‘soft Brexit’ – whether Labour’s or May’s (or Hunt’s or Gove’s) – now really looks dead. No-deal or no Brexit may well be the choice that looms for all sides as we hurtle towards that October 31 deadline.