New analysis by centre-right think-tank Onward, which uses the same methodology that correctly identified the ‘Red Wall’ in 2019, has found that 36 additional Labour-held seats in the North –including 18 in Yorkshire – would be vulnerable to the Conservatives at the next election if overall vote share is in line with 2019.

It said the findings mean that delivering on ‘levelling up’ promises is essential to Tory success at the next vote.

The research, which examined where parties’ vote share over-performs or under-performs relative to factors such as age, education and home-ownership, highlights Hemsworth, Hull East and Yvette Cooper’s Normanton, Pontefract and Castleford constituencies as top target seats for the Conservatives at the next election.

Boris Johnson's Red Wall success in the 2019 General Election could be repeated again, research has suggested.

While 18 Labour-held seats in Yorkshire and Humber are listed as having the likely potential to change hands because of demographic changes, just one Tory seat – Keighley – is seen as a key ‘battleground’ seat.

Onward said the shifting political centre of gravity means views of the Conservatives as the party of the South and Labour representing the North are increasingly outdated.

The report states that while Conservative support in the South is gradually drifting away, it is unlikely to have a major effect at the next election, meaning the Tories should prioritise holding on to seats in the North and Midlands won in 2019 and targeting further regional victories.

The report found that even in the event of a perfectly-executed electoral coalition between Labour and the Liberal Democrats in which the two parties effectively do not compete against each other, it is likely that the Conservatives would still retain a Parliamentary majority.

In Yorkshire, such a pact would see Labour only gain three seats – Dewsbury, Keighley and York Outer, while the Liberal Democrats would makegains.

However, the report warned the Conservatives’ position could be more threatened by the emergence of a new Ukip-style party that would split right-wing votes. Its analysis suggested such a party could cost the Tories 53 seats, resulting in a hung Parliament. In contrast, a Labour-Lib Dem pact would lose the Tories 44 seats.

In a sign of the challenge facing Labour, the research suggests the party could regain 31 seats in the North, Midlands, and North Wales if 2019 Conservative voters switched back to their preferred party, but only three southern seats would change hands.

Will Tanner, Director of Onward and former Deputy Head of Policy to Theresa May, said: “The next election, like the last, will be won in the North of England. While the South is steadily becoming less Conservative over time, there is no Blue Wall waiting to fall across the Home Counties in two years’ time. But there are dozens of traditional Labour seats in the North that could yet switch. This report underlines why making headway on ‘levelling up’ is utterly essential for the Conservative Party –and why Labour still has a mountain to climb.”

James Blagden, chief data analyst and head of Onward’s Future Politics programme, said: “The heart of the Tory Party has been shifting northwards for the last 30 years. Since Margaret Thatcher’s 1983 landslide, there has been a steady decline in Conservative support in London and the Home Counties and growth in the North and the Midlands.

“That trend is set to continue. But the greatest short-term concern for the Conservatives should be backsliding in the Red Wall, putting their majority at risk. The Conservatives stand on shaky ground, with their 2019 gains not yet secure and southern heartlands slowly drifting away.”

William Hague backs findings

Former Tory leader and Yorkshire MP William Hague has said the findings are “important reading for Conservatives”.

He said: “This is a timely and clear-sighted report on the central issue in British

electoral politics – can the new Conservative coalition be maintained?

“It offers a persuasive antidote to the idea that Tories can only succeed in the north at the expense of the south, but carries its own warnings – this is important reading for Conservatives.”

What the analysis shows in Yorkshire

Onward has found that 21.8 per cent of battleground seats (using the Red Wall-style over-performance methodology) are in Yorkshire. 18 of them are opportunities for the Conservatives to gain ground and only one is a potential loss to Labour.

Conservative majority

Keighley - 2,218

Labour lead over Conservative

Hemsworth - 1,180

Kingston upon Hull East - 1,239

Normanton, Pontefract and Castleford - 1,276

Wentworth and Dearne - 2,165

Doncaster Central - 2,278

Doncaster North - 2,370

Halifax - 2,569

Kingston upon Hull West and Hessle - 2,856

Rotherham - 3,121

Batley and Spen - 3,525

Barnsley East - 3,952

Sheffield South East - 4,289

Sheffield, Hallam - 5,013

Barnsley Central - 6,912

Kingston upon Hull North - 7,593

Sheffield, Heeley - 8,520

Leeds West - 10,564

Leeds North West - 10,749

Onward selected 'Labour lead over Conservative' as its measure due to the Brexit Party finishing second in Barnsley East and Barnsley Central and the Liberal Democrats finishing second in Sheffield Hallam at the last election.

The thinktank says that a 'perfect' Lib-Lab pact would only gain Labour three seats in Yorkshire (Dewsbury, Keighley and York Outer) compared to 21 seats nation-wide. Lib Dems would not make any gains.

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