Jeremy Corbyn’s Commons seat is set to be abolished, according to a copy of the parliamentary boundary review leaked today.

The Labour leader’s Islington North constituency will be split between those currently filled by his political allies and North London neighbours Emily Thornberry and Diane Abbott.

Corbyn, who celebrates one year in post today, appears to be one of the most high-profile victims of the review – alongside Tatton MP and former Chancellor George Osborne – which was carried out by the Boundary Commission and was due to be published tomorrow.

Corbyn faces being thrown into a battle for a seat alongside Abbott, who currently represents Hackney North and Stoke Newington, and Thornberry, MP for Islington South and Finsbury.

The review was set up as part of a highly controversial attempt by former prime minister David Cameron to cut the number of MPs from 650 to 600 – a move that would hit Labour worse than any other party. Details were leaked to the London Evening Standard today.

Chuka Umunna, MP for Streatham, has been spared the process of a lengthy competition, LabourList understands. Most of the former shadow Cabinet minister’s existing seat will go into a new constituency of Streatham and Mitcham, for which he is the only MP to meet the threshold to have a claim on it.

Labour MPs opposed to Corbyn’s leadership have long feared the boundary review could be used to remove them from the Parliamentary Labour Party or throw them into divisive battles with the colleagues for redrawn parliamentary seats.

Corbyn is expected in Brighton this evening for the traditional dinner between the Labour leader and trade union general secretaries.

TUC annual congress runs from Sunday 11 to Wednesday 14 September in Brighton. To see the rest of our coverage go to LabourList’s trade unions page.