By any standard, the Conservative Party’s victory in the Old Bexley and Sidcup by-election was decisive. The party’s candidate, Louie French, notched up 51.3 per cent of the vote in a contest caused by the untimely death of James Brokenshire. Governments often come unstuck in mid-term by-elections and so Boris Johnson is entitled to feel relieved.

Nevertheless, the slump in the party’s majority should serve to guard against complacency. There was a 10 per cent swing to Labour, but it is not their showing that ought to trouble Conservative strategists; instead they should be looking at the 6.6 per cent total notched up by Richard Tice, the leader and co-founder, with Nigel Farage, of the Reform UK Party. The Tories can well remember the damage that pair once did with the Brexit Party, their present party’s prior incarnation.

After the Bexley result Mr Tice claimed: “The British political landscape has changed tonight. There are now five parties in the British landscape.”

That remains to be seen, but with policies aimed at cutting taxes, and opposing “unnecessary” Covid restrictions, Reform UK is pitching its appeal straight at traditional Tory voters, who have been growing increasingly concerned by tax rises, looming inflation and broken promises over social care and the NHS.

The Conservatives now face another by-election – this time in North Shropshire, the seat vacated by Owen Paterson, on December 16 – where they are defending a 20,000-plus majority. Tice declared that the personality and policies of Boris Johnson were a “liability, not an asset” in Bexley. His theory will be tested again in short order.