When the Hartlepool by-election was announced speculation began to mount instantly about whether Labour would be able to hold the seat.
Once considered a safe-seat for the party, Hartlepool’s support for Labour has been up and down in recent years.
But with a government that’s been in power for 11 years and a majority of a few thousand to defend, losing the seat on 6 May would be considered a disaster for Sir Keir Starmer’s Labour.
Who is expected to win?
Despite their majority, and having held the seat for several decades, neither the pollsters or the bookmakers currently have Labour’s candidate as the favourite to win.
Dr Paul Williams came in second place in a poll conducted last month by Survation, to the Conservative’s Jill Mortimer.
The same goes for their current odds, with Mortimer the favourite to win according to Ladbrokes.
Opinion polling on the by-election is limited, and can only ever provide an estimate of what’s likely to happen, while political odds reflect where bets are being placed rather than wider public opinion.
But these predictions will still make grim reading for Labour, who should really be expected to retain the seat.
If the Conservatives are able to take the seat, it will be only the fifth time an incumbent government has gained a seat in a by-election since 1930.
While the Labour majority of 3,595 is not enormous, it would be the largest majority overturned by an incumbent government in a by-election in modern political history.
For the Conservatives, a win in Hartlepool would further cement their foothold in northern England, and bolster Boris Johnson’s leadership.
Analysis - What would a loss mean for Labour and Starmer?
Starmer took over the leadership of the Labour party in the midst of a pandemic, and after the party’s worst electoral defeat in decades.
He has had a difficult task trying to cut a balance between constructive opposition during a national crisis, and fulfilling the vital role of holding the government to account.
While his supporters say he has done a good job of helping the party’s brand recover after Jeremy Corbyn’s leadership, his personal polling has started to drop in recent weeks, and critics feel he is yet to show voters what he really believes in.
The Hartlepool by-election, which is the first since Starmer took over the party, the first of this parliament, and the first since the pandemic, will be a major test for Labour.
A major story of the 2019 general election was Labour losing seats in former heartlands in the north of England.
Critics of the party’s left-wing have sought to pin this on Corbyn as an individual, while others have pointed to longer term trends in Labour’s vote-share in these areas and some of the party’s vocal opposition to Brexit.
Hartlepool was one of a handful of places, like Hull, where Labour was able to retain seats despite hemorrhaging support, because the Brexit Party stood and attracted the votes of many people who might otherwise have voted Tory.
The Brexit Party still exists, in a new guise as Reform UK, but it seems unlikely their appeal will be anything like as great now.
Hartlepool is a particularly prickly test for Starmer, as it was retained twice under Corbyn, with the largest majority in more than a decade in 2017, and by a few thousands votes in 2019.
Holding the seat by a similar margin to 2019 would do little to show that Starmer is an improvement on Corbyn, in the kind of seat where his appeal and strategy in leadership so far should have had the most effect.
Losing the seat, after his predecessor maintained it twice, will force those who back Starmer to face up to some serious questions about his suitability for the role.
A bad performance in Hartlepool and in the local elections more generally is unlikely to prompt a serious leadership challenge against Starmer, but it will certainly ramp up the pressure on him.
And should Labour take one of it’s main targets on 6 May, the West Yorkshire mayoralty, it will prompt another ‘red-wall’ by-election where the conditions are perhaps even less favourable for Labour.