Labour leader Jeremy Corbyn's seat in Parliament could be abolished under proposals from the Boundary Commission for England.
Mr Corbyn represents the Islington North constituency in London, and much of it is expected to form part of a new Finsbury Park and Stoke Newington seat.
Mr Corbyn would be entitled to seek selection as Labour's candidate.
A source close to the Labour leader said there was "every reason to believe Jeremy will have a seat to contest".
The total number of MPs is to be reduced from 650 to 600 under government plans.
The boundary commissions for England and Wales are drawing up plans for new constituencies, with proposed details being published on Tuesday.
The Labour Party is expected to be particularly hard hit by the changes.
Proposed changes to the boundaries in Northern Ireland have already been published.
The proposed changes in Scotland are set to be published next month.