Ministers have U-turned on proposals to cut the number of MPs from 650 to 600, citing an increased workload after Brexit.
The idea had first been implemented by David Cameron when he was prime minister but Boris Johnson’s administration will row back on the bid to take 50 MPs off the public payroll.
Constitution minister Chloe Smith confirmed there had been a “change in policy”.
She said the Government would no longer follow through on the recommendations of the 2018 boundary review, which had been instructed to reduce the number of constituencies to 600 and redraw them to have near-equal electorates.
A number of high-profile MPs would have seen their seats wiped out as part of the Boundary Commission’s shake-up, including Labour leader Jeremy Corbyn and ex-Brexit secretary David Davis.
Some pollsters predicted that the radical reshaping of the electoral map could have even put the Prime Minister’s own seat of Uxbridge and South Ruislip at risk at the next election.
Cabinet Office minister Ms Smith said the Government remained committed to creating constituencies with near-equal numbers of voters but that it was “sensible” for there to continue to be 650 MPs.
In a written statement, the Conservative MP wrote: “The Government is minded to instead make provision for the number of parliamentary constituencies to remain at 650.
“This is a change in policy from the position previously legislated for under the coalition government.
“Since that policy was established in the coalition agreement, the United Kingdom has now left the European Union.
“The UK Parliament will have a greater workload now we are taking back control and regaining our political and economic independence.
“It is therefore sensible for the number of parliamentary constituencies to remain at 650.”
She revealed that the Government, as well as bringing forward legislation to block the implementation of the 2018 overhaul, would call for boundary reviews to take place every eight years rather than every five.
It would mean boundaries would be in place for at least two general elections before being reconsidered.
The four constituencies which were protected from plans to re-organise electorate numbers – Orkney and Shetland, Na h-Eileanan an Iar, and two seats for the Isle of Wight – will continue to have special status, Ms Smith said.
The Electoral Reform Society said cutting the number of MPs would have shifted the power balance in ministers’ favour.
Chief executive Darren Hughes said: “Plans to cut voters’ representation in the Commons would have undermined the voices of ordinary people in Parliament and hurt democratic scrutiny.
“The proposals always seemed more like an executive power grab than a genuine move to improve the function of the Commons, so this is a small but welcome victory for backbenchers and voters.
“Without shrinking the size of the Government, cutting MPs would have done little more than enhance the already disproportionate power of ministers.”
The campaign group urged the Government to turn its attention to “reducing the number of unelected peers in the bloated House of Lords” once the coronavirus pandemic is over.