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Final recommendations for new parliamentary boundaries that could see the number of MPs cut from 650 to 600 will be published later.
The Boundary Commission for England submitted its proposals to the government, but they must now be presented to Parliament.
The commission said it was "confident" in its new map, which covers constituencies across the UK.
Parliament approved the principle of reducing the number of MPs in 2011.
Since then, the Boundary Commissions of England, Scotland, Wales and Northern Ireland were meant to redraw the UK's political map every five years to take account of changes in population shifts.
The reduction in the number of parliamentary constituencies was meant to happen while the Coalition government was in power between 2010 to 2015.
But it was abandoned in 2013 after the Liberal Democrats withdrew their support, having failed to agree on House of Lords reform with their Tory partners.
As a result, the 2015 election was fought on the same boundaries as in 2010, as was the snap general election in 2017.
The proposed number of seats for the next election are:
- England: 501 (down from 533)
- Scotland: 53 (down from 59)
- Wales: 29 (down from 40)
- Northern Ireland: 17 (down from 18)
As well as reducing the number of seats, the review aims to make constituencies more equal in size, in terms of their total number of votersbetween 71,031 and 78,507.
The Commission's earlier proposalsbased on the electoral register from December 2015have been significantly altered following a public consultation, in which thousands of responses were received.
If MPs reject the proposals, the next election will be fought on demographic data based on the 2000 electoral register and will not take into account changes since then.
Secretary to the commission, Sam Hartley, said: "We're confident that the new map of constituencies best reflects the rules set for us by Parliament and we're especially pleased that our recommendations are based heavily on what members of the public have told us about their local areas.
"It is now up to the government to present our report to Parliament, and we look forward to being able to publish our recommendations once that has happened."
The BBC's political correspondent, Peter Saull, said critics of the changes have warned that Brexit will mean more legislation in the coming yearsand fewer MPs means less parliamentary scrutiny.
he also stated that Labour had accused the government of "gerrymandering", with the changes expected to most benefit the Conservatives at the ballot box.
But the Tories have insisted the system is currently weighed against them and the boundariesdecided by population figuresare out of date.