Labour leader Jeremy Corbyn's Islington North constituency is one of 50 to be abolished at the next general election, under proposals published by the Boundary Commission for England.
And to add more insult to injury, the shake-up of seats in north London, which sees the constituency he has represented since 1983 split into Islington and Finsbury Park & Stoke Newington, potentially pits him against two of his closest lieutenants - shadow health secretary Diane Abbott and shadow foreign secretary Emily Thornberry.
Corbyn said he was "very unhappy" about boundary changes which could affect his constituency in North London. Speaking as he arrived for a private dinner with the TUC general council in Brighton, he said he was "very confident" about the future, adding there was a long way to go before any suggested changes came into effect.
Corbyn's leadership rival Owen Smith, meanwhile, sees his Pontypridd seat merged with the neighbouring Cynon Valley constituency of veteran backbencher Ann Clwyd.
Others facing significant changes which could leave them vulnerable to de-selection attempts by hardline Corbynistas include Chuka Umunna (Streatham), Yvette Cooper (Normanton, Pontefract and Castleford) and Tristram Hunt (Stoke-on-Trent Central).
The planned reduction of the size of the House of Commons from 650 to 600 MPs is expected to hit Labour hardest, with more constituencies abolished or merged in strongholds such as London, Wales, the North-East and North-West than the Tory-dominated areas.
The party has signalled it will fight the "unfair, undemocratic and unacceptable" changes, stressing they are based on an "out of date" version of the electoral register from 2015 and do not include two million voters who signed up to vote in the EU referendum.
Theresa May's Maidenhead seat remains as it is, while Chancellor Philip Hammond's Runnymede and Weybridge is largely unchanged.
Foreign Secretary Boris Johnson (Uxbridge and South Ruislip) also faces a substantial redrawing of the electoral map, but would appear well-placed to secure the Conservative nomination for the new seat of Hillingdon and Uxbridge.
The seats of Cabinet colleagues such as Liam Fox, Jeremy Hunt and Amber Rudd escape unscathed, but Brexit Secretary David Davis sees his Haltemprice & Howden constituency in East Yorkshire cut in two.
Some other points that have emerged so far from the England Boundary Commission's initial proposals include ...
* Ukip's sole MP Douglas Carswell sees half his Clacton constituency taken away in a shake-up with the establishment of a new Harwich & Clacton seat.
* Tory former chancellor George Osborne's Tatton constituency is axed, with a small remnant going into a new Altrincham & Tatton Park seat.
* Among historic seats to go, the Rushcliffe constituency represented by Tory former cabinet minister Ken Clarke since 1970 is set for abolition.
* Commons Speaker John Bercow sees minor changes to his Buckingham constituency in which he originally was elected as a Conservative.
* There is no change to Tory former prime minister David Cameron's seat of Witney, where a by-election is now due to take place after his decision to step down as an MP.
* The Batley & Spen constituency of Labour's Jo Cox, who died in June after being shot and stabbed, will disappear, to be replaced by two new seats: Batley & Morley, and Spen. A by-election is also pending here.