If the Conservatives lose one or both of Thursday’s by-elections in Kingswood and Wellingborough, it would mean the Government has clocked up more by-election defeats in a single parliament than any government since the 1960s.

The Tories’ current tally of by-election losses since the 2019 general election is eight: Chesham & Amersham and North Shropshire in 2021 (both gained by the Liberal Democrats); Tiverton & Honiton and Wakefield in 2022 (won by the Lib Dems and Labour respectively); and Selby & Ainsty, Somerton & Frome, Mid Bedfordshire and Tamworth in 2023 (all Labour gains except Somerton & Frome, which was won by the Lib Dems).

The last government to lose this many by-elections during a single parliament was the 1992-97 Conservative administration led by John Major.

If the Tories lose one or both of Thursday’s contests, it would bring to nine or 10 the number of defeats so far this parliament: more than any previous government since the 1966-70 Labour administration of Harold Wilson, which endured 15 losses.

Even accounting for the Conservatives’ one by-election gain this parliament – winning Hartlepool from Labour in 2021 – a double defeat on Thursday would bring the party’s overall by-election scorecard to nine net losses (10 defeats, one gain).

This would still be worse than any government since 1966-70.

(PA Graphics)

Here are some of the key statistics and historical benchmarks behind the two contests:

– Kingswood

Chris Skidmore won the Gloucestershire constituency for the Conservatives at the past four general elections, increasing his share of the vote on each occasion, from 40% in 2010 to 49% in 2015, 55% in 2017 and 56% in 2019.

Before 2010, Labour had won the seat at every general election since 1992.

This week’s by-election was triggered by Mr Skidmore’s resignation as MP in January, in protest at Government legislation to boost North Sea oil and gas drilling.

He had previously announced his intention to stand down at the next general election, when the constituency is being abolished.

POLITICS Skidmore
(PA Graphics)

Labour came second in the seat at each of the past four general elections and is the main challenger in Thursday’s contest.

To win, the party needs a swing in the share of the vote of 11.4 percentage points.

This is the equivalent of a net change of 12 in every 100 people who voted Conservative in 2019 switching sides.

It is a much smaller swing than the ones achieved by Labour in its recent by-election successes against the Tories, such as 23.9 percentage points at Tamworth, 23.7 points at Selby & Ainsty and 20.5 points at Mid Bedfordshire.

There are six candidates standing in the by-election: Sam Bromiley (Conservative), Andrew Brown (Liberal Democrat), Damien Egan (Labour), Lorraine Francis (Green), Rupert Lowe (Reform) and Nicholas Wood (Ukip).

The abolition of the constituency at the next general election – which has to take place by law no later than January 2025 – means whoever wins the by-election will represent the seat for only a few months.

– Wellingborough

The Northamptonshire constituency was won by Peter Bone for the Conservatives at every general election from 2005 to 2019.

He increased the Tories’ share of the vote at each poll, pushing it up from 43% in 2005 to 48% in 2010, 52% in 2015, 57% in 2017 and 62% in 2019.

Labour came second in four of the five contests, the exception being 2015 when Ukip was runner-up.

Further back, Labour won Wellingborough at the 1997 and 2001 general elections.

POLITICS Bone
(PA Graphics)

The chain of events that led to the by-election began when Mr Bone received a six-week suspension from the House of Commons after an inquiry found he had subjected a staff member to bullying and sexual misconduct.

The suspension triggered a recall petition in his constituency which was signed by more than 10% of voters – the threshold for an MP to be removed from their seat.

The by-election is similar to Kingswood in that is it a two-horse race between the Conservatives and Labour.

However, the swing needed by Labour to win the seat is larger, at 17.9 percentage points – in other words, the equivalent of a net change of 18 in every 100 people who voted Tory in 2019 switching sides.

This is still a smaller swing than the ones managed by Labour in 2023 at the by-elections in Tamworth, Selby & Ainsty and Mid Bedfordshire.

There are 11 candidates standing in this by-election: Nick the Flying Brick (Official Monster Raving Loony), Ana Gunn (Liberal Democrat), Ben Habib (Reform), Helen Harrison (Conservative), Ankit Love Jknpp Jay Mala Post-Mortem (no description), Gen Kitchen (Labour), Alex Merola (Britain First), Will Morris (Green), Andre Pyne-Bailey (Independent), Marion Turner-Hawes (no description) and Kev Watts (Independent).

The constituency of Wellingborough is being replaced at the next general election by the new seat of Wellingborough & Rushden.