The Conservatives are being hit by a massive political tide turning against them as Labour won two historic by-election wins on Friday.
Labour’s victories in Mid-Bedfordshire and Tamworth mean that of the 10 seats to have changed hands at parliamentary by-elections in the past three years, eight of them involved monumental swings of 20 percentage points or higher.
This is a pattern that is unprecedented in recent political history.
By-elections are often used by voters to punish the Government of the day, so need to be treated with caution, and turnout was low in both of the polls on Thursday, suggesting many Conservative voters stayed at home which they may not do at a General Election.
However, the scale of the swings and the number of them will alarm many Tory MPs with smaller majorities who will fear a major political change is sweeping the country, possibly partly due to the salience of Brexit having dramatically dropped since the 2019 election.
Sir Keir Starmer’s party seized Mid-Bedfordshire, overturning the largest numerical Conservative majority (24,664) at a by-election since 1945, or possibly ever.
The seat has existed since 1918 and had elected Tory MPs continuously since 1931 - until now.
To win Mid-Bedfordshire, Labour needed a swing in the share of the vote of 19.1 percentage points.
They managed a swing of 20.5 points, almost matching the 20.4 point swing the party achieved at the Rutherglen & Hamilton West by-election earlier in October, when they won the seat from the SNP.
The Conservative share of the vote in Mid Bedfordshire fell from 38 per cent at the 2019 general election to 31 per cent, while Labour jumped from 22 per cent to 34 per cent.
In Tamworth, Staffordshire, Labour pulled off an even bigger swing of 23.9 points: high enough to rank as the second largest swing recorded by Labour at a by-election since 1945.
The largest was 29.1 points at the Dudley West by-election in December 1994.
The Conservative majority overturned by Labour in Tamworth was 19,634: smaller than in Mid Bedfordshire, but still a sizeable number.
The Tories’ share of the vote dropped sharply from 66 per cent at the 2019 general election to 41 per cent, while Labour’s share rose from 24 per cent to 46 per cent.
The two by-election results have not only set new historical records - they also mean a total of 10 seats have changed hands at parliamentary by-elections in the past three years.
This is a level of churn not seen since the 1990s, when Sir John Major was Prime Minister and the Tories had clocked up almost 18 years in power at Westminster
Sir John Curtice, Professor of Politics at Strathclyde University, told the BBC: "Both swings to Labour were much closer to the 24 point swing in July in Selby and Ainstey than the more modest seven point swing in Uxbridge.
"Tory MPs hoped that the result in the London seat in the summer pointed to a potential pathway back to electoral recovery. Now it looks rather more like a mirage.
"It looks as though Rishi Sunak will have to achieve what John Major proved unable to deliver before 1997 - a dramatic reversal of a public mood that is inclined to turf the Conservatives out of office. He now knows that will not be easy."
Of the 10 seats to have changed hands at parliamentary by-elections in the past three years, eight of them involved swings of 20 percentage points or higher: a pattern that is unprecedented in recent political history.
Five of these eight swings have occurred in the past four months: Selby & Ainsty (23.7 points from Conservatives to Labour) and Somerton & Frome (29.0 points from Conservatives to the Liberal Democrats) in July; Rutherglen & Hamilton West (20.4 points from the SNP to Labour) earlier this month, and now Mid Bedfordshire (20.5 points) and Tamworth (23.9 points), both from Conservatives to Labour.
The others were Tiverton & Honiton (29.9 points) in June 2022, North Shropshire (34.1 points) in December 2021, and Chesham & Amersham (25.2 points) in June 2021, all from the Conservatives to the Liberal Democrats.
The remaining two seats to have changed hands at by-elections in the last three years are Wakefield, gained by Labour from the Conservatives in June 2022 on a swing of 12.7 points; and Hartlepool, gained by the Tories from Labour in May 2021 on a swing of 16.0 points
The outcome in Tamworth has an intriguing parallel with a by-election in the 1990s.
Before 1997, this area of the country was represented by the constituency of South East Staffordshire.
A by-election took place in South East Staffordshire in April 1996, roughly one year ahead of a general election.
Then, as now, the Conservatives went into the contest defending a large majority.
And then, as now, Labour won the seat on a huge swing: 22.1 percentage points, very close to the 23.9 point swing they achieved in Tamworth on Friday.
