Suffolk’s only Labour MP could find it harder than ever to retain his Ipswich seat at the next general election if Boundary Commission recommendations are implemented.

The proposed new boundaries would see little change in Suffolk – the county would retain seven MPs – even though across the UK the number of MPs would fall from 650 to 600.

Three constituencies – West Suffolk, Waveney, and Suffolk Coastal – would be unchanged after the changes and there would be minor changes between South Suffolk, Central Suffolk and Bury St Edmunds but they would be likely to have little electoral effect because they are all safe Conservative seats.

However the one significant change is a proposal to move Castle Hill, a solidly Tory ward, from the safe Central Suffolk and North Ipswich seat into marginal Ipswich.

In 2017 Labour’s Sandy Martin had a majority of 831 when he snatched the seat from Ben Gummer. Had Castle Hill been included in the Ipswich seat, the result could well have been different.

The proposed changes are seen to be good for the Conservatives – election experts estimate that if the 2017 election had been fought on these boundaries, Theresa May would have ended up with a majority of 16 in the House of Commons.

But it is not certain that they will be accepted by MPs – many Conservatives could face the prospect of losing their safe seats or having to fight their colleagues for the right to stand again.

Mr Martin said he was relaxed about the prospect of having Castle Hill moved into his seat: “Recently it has returned Conservative councillors, but that has not always been the case.” In the early to mid 1990s Castle Hill often returned Labour councillors.

He added: “I really don’t know whether Conservative MPs will vote for this, but I don’t really think the result of the next general election in Ipswich will depend on whether Castle Hill is in the constituency – it will depend on the campaigns in the town.”

Labour is opposed to the boundary changes because the party does not believe it is right to cut the number of MPs, especially as they could have more work to do because there will be no MEPs after the UK pulls out of the European Union next year.

MP for Central Suffolk and North Ipswich Dr Dan Poulter said “I’m very sorry indeed to lose Castle Hill ward under the terms of the new Boundary Review.

“I have always worked hard and tried my best for the people of Castle Hill, including helping in the campaign to get Broomhill Pool re-opened as a lido and community facility, and keeping Broomhill Library open for the local community.

“I am sorry that the Boundary Review will result in Castle Hill ward moving out of my Constituency after the next election, as over the past eight years, I have worked hard to support the local community there.

“However, any changes will not come into force until Parliament has agreed the recommendations of the Boundary Commission; until then, I shall continue to do all that I can to support the residents of Castle Hill.”