It has been impossible for weeks to find a Tory who thought they would win the Blackpool South by-election.
The party's previous MP left under a cloud, and it only required a 5.5 per cent swing to turn the seat red.
But at 26 per cent, the scale of the swing to Labour will still have come as a huge blow to Rishi Sunak.
That reinforces the idea that Keir Starmer is on track for power – and will set MPs' nerves jangling.
However, perhaps what will alarm them most is the Reform performance.