St John’s Wood and Maida Vale will join Kensington while Marylebone will be grouped with Belsize Park under major changes to the political map announced this week.

Westminster is currently split between two constituencies – Westminster North and Cities of London and Westminster – but proposals drawn up by the Boundary Commission will see the borough split three ways.

Eight wards from the north-western part of Westminster will join a newly-formed Paddington constituency which will also take in four wards in north Kensington.

Four wards in the north-eastern part will join a constituency dominated by seven Camden wards as part of a Camden and Regent’s Park seat.

The remaining seven wards in the central and southern part of Westminster will be grouped with eight wards from Kensington and Chelsea in a new Westminster and Kensington seat.

The changes, which are subject to public consultation, are based on new government rules which will see the number of London seats reduced from 73 to 68.

North Westminster Labour MP Karen Buck says she is likely to move over to the Paddington seat which follows similar lines to her previous Regent’s Park and Kensington North constituency.

“From my point of view Westminster North was very marginal but Paddington will, on the face of it, be less marginal,” she said. “The arithmetic looks more hopeful for Labour.

“The problem locally is I think it’s a great shame to take two wards [Church Street and Regent’s Park] from North Westminster and place them in what is essentially a Camden parliamentary seat.

“In terms of properly representing the local community that’s not a good thing.

“Its deeply distressing losing wards because you do feel a very strong connection to areas that you have worked with for a long time.

Mark Field, Conservative MP for Cities of London and Westminster, said he could contest the Westminster and Kensington constituency although he may face a battle with fellow Tory MP Sir Malcolm Rifkind of Kensington.

“It would make sense to move across but there’s the potential that the two of us would be going for the same seat as the primary part of both of our seats has ended up in the constituency,” he said. “What has surprised all of us is quite how disruptive the proposals are. It has come as a bit of a shock.

“It’s very disappointing on a personal level to lose wards that I have worked hard on for 10 years.”

To take part in the consultation, visit http://consultation.boundarycommissionforengland.independent.gov.uk before December 5.