Theresa May could have retained her House of Commons majority if June’s snap General Election had been fought on a proposed shake-up of MPs’ constituencies.
An analysis of plans to cut the number of parliamentary seats, from 650 to 600, reveals if the vote had been held on a new list of constituencies the Conservatives may well have won an overall majority – rather than have to rely on the DUP’s support to rule as a minority administration.
The research, carried out for Sky News, the BBC, ITV News and the Press Association, suggests the Tories would have enjoyed a majority of 16; or effectively 25 if Sinn Fein were assumed not to take up their seats.
Conducted by Professors Colin Rallings and Michael Thrasher, emeritus professors of politics at the University of Plymouth and associate members of Nuffield College, Oxford, the work will pressure the Prime Minister to push for boundary changes before the next General Election.
However, the seats shake-up – the latest version of which has been proposed by boundary commissions in England, Wales and Scotland – is unlikely to get through Parliament due to Mrs May’s lack of majority and fierce resistance from Opposition parties.
:: North London battle for Labour MPs
Labour signalled their rejection of the latest proposals to alter the UK’s constituencies, as it was revealed Jeremy Corbyn could face a battle with some of his closest left-wing allies to stay in Parliament.
The Labour leader’s constituency is set to be axed under the plans, potentially plunging him into a fight with parliamentary neighbours Emily Thornberry, the shadow foreign secretary, and Diane Abbott, the shadow home secretary.
Mr Corbyn, who has represented Islington North for 34 years, and his shadow cabinet allies are under threat because of a major shake-up of seats in north London.
The Labour leader bitterly attacked the proposal to scrap his own seat when it was first announced last year, claiming it was based on an out-of-date version of the electoral register.
At the moment, Ms Thornberry is MP for Islington South and Finsbury and Ms Abbott is MP for Hackney North and Stoke Newington.
The new plans propose a single Islington seat and a new Finsbury Park and Stoke Newington constituency.
Meg Hillier, MP for Hackney South and Shoreditch, could also be drawn into the battle.
So too could David Lammy, the high-profile MP for Tottenham, and Kate Osamor, the Corbyn-backing shadow international development secretary and Edmonton MP.
The plans could even possibly have an impact on Sir Keir Starmer, MP for Holborn and St Pancras and the shadow Brexit secretary, who is tipped by some Labour MPs as a potential party leader.
:: Top Tories could go head-to-head
The revised constituency list by the Boundary Commission for England also spells trouble for Boris Johnson, whose Uxbridge and South Ruislip constituency faces the threat of abolition.
For the Foreign Secretary, unless the proposals to axe his seat are overturned, his best hope is to switch to a new constituency of Hillingdon and Uxbridge, which includes large parts of his old seat.
Tory MPs could also be forced to go head-to-head in Essex, where the county faces losing one MP.
International Development Secretary Priti Patel and rising star James Cleverly may have to fight for the same seat.
:: SNP and DUP badly hit
The SNP, many of whose MPs have tiny majorities after June’s election, are badly hit by plans by the Boundary Commission for Scotland to redraw the political map north of the border.
The seat of the SNP’s Westminster leader Ian Blackford, the Ross, Skye and Lochaber constituency formerly represented by the late Liberal Democrat leader Charles Kennedy, is axed as Highland constituencies are cut from three to two.
Also due to disappear is the SNP’s former deputy leader Stewart Hosie’s Dundee East seat, largely absorbed into a proposed Angus South and Dundee East constituency.
Wales is set to lose 11 of its 40 seats and the Welsh Secretary Alun Cairns, whose majority in Vale of Glamorgan in June was only a little over 2,000, is likely to be in difficulty.
In Northern Ireland, the proposals are bad news for the Unionist parties – meaning they will be bitterly opposed by the Tories’ Commons allies the DUP – and good news for Sinn Fein.
Cutting the number of MPs to 600 was originally proposed by David Cameron when he was Opposition leader at the height of the MPs’ expenses scandal in 2009.
It was dropped after opposition from Mr Cameron’s partners in the Coalition Government, the Liberal Democrats, and some Tory MPs.
But it was in the Conservative manifesto in both 2015 and this year.
There will now be an eight-week consultation on the shake-up, lasting until 11 December, which is likely to see political parties and individual MPs raising strong objections to many of the proposed changes.
But, backing the shake-up, the Government’s Constitution minister Chris Skidmore said: “A boundary review is needed to ensure fair and equal representation for the voting public across the UK by the next general election.
“Without any boundary reforms, constituencies would be based on data that is over 20 years old.
“This would disregard significant changes in demographics, house building and migration.”
Cat Smith MP, Labour’s shadow minister for voter engagement and youth affairs, said: “Labour stands ready to work with all parties to ensure that a boundary review can go ahead in a way that benefits our democracy, not just the Conservative Party.
“However it has been clear from the start that the Tories have only been interested in their own political advantage rather than what is in the best interests of the country.”
And the Liberal Democrat chief whip Alistair Carmichael called on the Government to stop wasting money on a “dead-duck” boundary review and scrap it.
“The DUP will not wear this review,” said Mr Carmichael.
“Nor will many Tory backbenchers. The Government should stop wasting public funds and bow to the inevitable.”