But when the result came, there was no political earthquake and Labour's Paulette Hamilton comfortably held on to the seat held by trade union and party stalwart Jack Dromey from 2010 until his sudden death from an heart attack in January.

Labour's share of votes goes up

Her majority of 3,266 was only slightly down on Mr Dromey's winning margin of 3,601 in December 2019, but Labour's share of the vote was up from 50% to 55%. The Tory share of the vote fell from 40% to 36%.

So there was no discernible Ukraine uplift for Boris Johnson, either. Speaking to Sky News after her victory, Ms Hamilton said people in the constituency were scared by what's happening in Ukraine, but she didn't believe it influenced how people voted.

The received wisdom in politics is that domestic crises and international emergencies like wars usually benefit a sitting prime minister at the polls, given their constant exposure on TV and the opportunity to play the world statesman. Think of 1982-83 and Margaret Thatcher and the Falklands War.

Just under a year ago, at a key point in the COVID crisis, Mr Johnson did appear to benefit from a "vaccine bounce", which was credited with helping him pull off a spectacular victory in the Hartlepool by-election, deep in Labour's former "red wall" territory.

In the same Sky News interview here, Birmingham Northfield's Conservative MP Gary Sambrook, who ran the Tories' by-election campaign, had all but conceded defeat, pleading that his party hadn't won Erdington since before his grandparents were born.

He claimed governing parties didn't win by-elections from their opponents. Well, as a general rule they don't. But as well as the Hartlepool triumph, the Tories won Copeland from Labour in 2017.

The old left isn't dead

As for Labour, during the Ukraine crisis Sir Keir Starmer has hammered home the message that his party has changed from Jeremy Corbyn's leadership and is now firmly the party of NATO. Sir Keir is no Ernest Bevin, Labour's charismatic post-war foreign secretary, however.

But the Labour leader even threatened to remove the whip from senior left-wingers like John McDonnell and Diane Abbott if they attended a Stop the War rally earlier this week.

Labour may have avoided a by-election catastrophe, but one post script of this by-election is that the old left isn't dead. It isn't even sleeping or resting, to misquote the famous Monty Python parrot sketch.

In a performance that will cheer up all veteran left-wing comrades and Starmer critics, the former Militant Tendency MP Dave Nellist, standing here for the Trade Unionist and Socialist Coalition, came third, ahead of the Lib Dems, Greens and Reform UK.

Again, not an earthquake, obviously. But a little tremor from the left as Sir Keir breathes a sigh of relief this morning that his Labour Party survived the real storms and some concerns about a possible Ukraine boost for the PM - and, in the end, won here fairly comfortably.