There's life in the Liberal Democrats yet. The Conservative majority in Witney has been slashed, with lawyer and nominative determinism case study Robert Courts elected, but with a much reduced majority.

It's down in both absolute terms, from 25,155 to 5,702, but it's never wise to worry too much about raw numbers in by-elections. The percentages tell us a lot more, and there's considerable cause for alarm in the Tory camp as far as they are concerned: the Conservative vote down from 60 per cent to 45 per cent.

(On a side note, I wouldn’t read much of anything into the fact that Labour slipped to third. It has never been a happy hunting ground for them and their vote was squeezed less by the Liberal Democrats than you’d perhaps expect.)

And what about those Liberal Democrats, eh? They've surged from fourth place to second, a 23.5 per cent increase in their vote, a 19.3 swing from Conservative to Liberal, the biggest towards that party in two decades.

One thing is clear: the "Liberal Democrat fightback" is not just a hashtag. The party has been doing particularly well in affluent Conservative areas that voted to stay in the European Union. (It's worth noting that one seat that very much fits that profile is Theresa May's own stomping ground of Maidenhead.)

It means that if, as looks likely, Zac Goldsmith triggers a by-election over Heathrow, the Liberal Democrats will consider themselves favourites if they can find a top-tier candidate with decent local connections. They also start with their by-election machine having done very well indeed out of what you might call its “open beta” in Witney. The county council elections next year, too, should be low hanging fruit for

As Sam Coates reports in the Times this morning, there are growing calls from MPs and ministers that May should go to the country while the going's good, calls that will only be intensified by the going-over that the PM got in Brussels last night. And now, for marginal Conservatives in the south-west especially, it's just just the pressure points of the Brexit talks that should worry them - it's that with every day between now and the next election, the Liberal Democrats may have another day to get their feet back under the table.

This originally appeared in Morning Call, my daily guide to what's going on in politics and the papers. It's free, and you can subscribe here.