Jeremy Corbyn and George Osborne are the most high-profile victims of parliamentary boundary changes that will see their constituencies scrapped.
A number of senior Government ministers and Brexit supporting Conservative MPs are also under threat and face a battle to remain as MPs including Boris Johnson, David Davis and Priti Patel.
Labour is expected to lose around 30 MPs in what will be the most significant change to the make-up of Parliament since the 1940s.
The Conservatives are likely to lose fewer seats but a number of senior Government ministers, including Justine Greening, the Education Secretary, are thought to be at risk.
On Monday night Mr Osborne, the former chancellor, acknowledged the plans mean “big changes” for his Tatton constituency, which will disappear completely, but he vowed to fight the 2020 election regardless and hinted that he could appeal against the decision.
He said: “I’m going to consider carefully whether they can be improved upon and whether to make representations. Whatever the final boundaries, I look forward to putting myself forward to voters for re-election for Cheshire in 2020.
One of the most high-profile casualties will be the Labour leader, whose Islington North constituency will disappear completely under the plans.
A source close to Mr Corbyn said they are confident he “will have a seat to contest” in the 2020 election, when the changes are due to come into force, but he will be forced to seek selection, probably for the new area of Finsbury Park and Stoke Newington, where he could face a battle with his ally Diane Abbott.
It is likely that the Labour leader will lay claim to the new seat created under party rules which state he can claim ownership of a new seat if 40 per cent of his constituents are resident there.
Mr Corbyn last night criticised the proposals. Speaking in Brighton he said: I’m very confident of the constituency changes that are suggested.
“But I have to say they are a long way off. I look forward to representing in parliament some part of Islington and some part of north London.
But I’m very unhappy with the size of the new constituencies. Many of these areas, such as the one I represent don’t need to be too big.”
But Ms Abbott and another senior Labour MP Emily Thornberry also face significant changes to their seats and could be forced to battle it out to stay in Westminster.
Chuka Umunna, Yvette Cooper and Tristram Hunt are among leading moderates facing significant changes which could leave them vulnerable to de-selection attempts by hardline Corbyn supporters.
The shake-up will also see half of Ukip’s sole MP Douglas Carswell’s Clacton constituency taken away with the establishment of a new Harwich & Clacton seat.
A number of senior pro-Brexit Tories could also face a fight to stay in the Commons.
Priti Patel, the International Development Secretary, David Davis, the Brexit minister, and Boris Johnson also face significant changes to their electorates and could be forced to seek election in another area of the country.
A source close to Mr Johnson said the changes are not catastrophic but could make it more difficult for the Foreign Secretary to get re-elected.
Conservative chairman Sir Patrick McLoughlin said the party would follow a policy of “no colleague left behind” to minimise the disruption to sitting MPs, hinting that those in danger could be found safe seats elsewhere.
“This constructive approach is in strong contrast to the Labour Party which is riddled with infighting and threats of deselection,” said Sir Patrick. “Momentum’s aim to use this process to boot out moderate Labour MPs is not an argument against these vital reforms, which will ensure fairness across the United Kingdom.”
The plans announced by the Boundary Commission for England will see 50 MPs scrapped from Westminster in a bid to make elections fairer and more representative.
But Labour claims the Conservatives are using the review to win a bigger majority in parliament after experts concluded that Theresa May’s influence could be increased from 12 to around 44.
On Monday night a party source said: “It looks like Theresa May is settling scores. Not many will be surprised that she’s using this process for her own political advantage, but most Tory MPs will be raising an eyebrow at how far she’s gone.
“It’s fair to say that if this were to go through she’d not only be hitting the Labour Party but she’d be ridding herself of some of her most bothersome MPs. It’s certainly bold but it’s high risk.
“Those in the firing line will no doubt cry foul and in doing so they could bring the whole shoddy edifice crashing down with it.
A separate review in Wales, to be unveiled tomorrow, could see Owen Smith’s seat scrapped.
There are also concerns about the way the review has been conducted and the data that has been used, which does not include the millions of people who signed up to vote in the EU referendum.
News Source TelegraphNews