Electoral officials have announced plans for the biggest shake-up of parliamentary constituencies in England in decades, one that critics immediately warned would break up many recognisable communities because of an overly strict set of rules. Among those affected would be Keir Starmer. The initial plan for the Labour leader’s London seat of Holborn and St Pancras would see it significantly rejigged and renamed as Kentish Town and Bloomsbury. Other recommendations by the Boundary Commission for England include the break-up of several longstanding, geographical-based seats, for example the Labour-held City of Chester, which has existed in various forms since the 16th century. Other well-known constituency names would also change or disappear. The existing Cities of London and Westminster seat, which includes Downing Street and parliament, would be split to become City of London and Islington south, and another new constituency, Westminster and Chelsea east. The plans are the latest stage in a marathon effort to update constituency boundaries that has been going on for a decade and which will see considerably more wrangling before the new map is theoretically finished in 2023. The rejig is a UK-wide operation, but each nation has its own Boundary Commission, and those for Scotland, Wales and Northern Ireland are not due to report until at least next month. The aim of the exercise is to make every constituency’s population of registered voters close to the average of just under 73,400, apart from a handful of “protected” seats. One of the main objections from Labour is that the various Boundary Commissions have been given a leeway of just 5% above or below the average, rather than the 10% the party hoped for. One Labour MP said this restriction had inevitably led to anomalous and arbitrary constituency divisions: “The numbers have primacy. If everything has to be so equal, it can’t take account of geography. And with a constituency system, people have to have a sense of belonging for it to work.” Even the broad template involves significant flux, given considerable existing differences in constituency size, and varying changes in population since the last completed review, which took place between 2000 and 2007 and came into force in 2010. Keeping the current total of 650 seats, the number in England will rise from 533 to 543, Scotland will lose two, down to 57, and Wales will plummet from 40 to 32. Northern Ireland will stay at 18. Within England, population patterns also mean big changes. The south-east of England gains seven new seats, London two, the east of England three, and the south-west also three. In contrast, there will be a drop of two in the north-east, north-west and West Midlands, and one fewer in the east Midlands, with no change in Yorkshire and the Humber. One of the paradoxes of the changes is that while one analysis calculated they could benefit the Conservatives by up to 10 seats according to 2019 voting patterns, the recent Tory advance into the north and Midlands means a number of their MPs could still lose out. The detailed regional reports published for England set out the scale of the task in having to adapt to the extent of the changes and the tight restrictions on numbers. The outline for London notes that of the 73 London constituencies, only two would emerge the same as before, while “significant change is required throughout most of London in order to comply with the permitted electorate range”. In the north-west, more than 80% of constituencies face change beyond alignment with new local government ward boundaries, with a similar proportion in the south-east and east of England. This is, however, just the start of the process. The Boundary Commission will now embark on a series of consultations, which will see numerous local constituency parties and councils lobby for changes. The process is never straightforward, and the last two efforts were abandoned in disarray, in 2013 and 2018, when the plan had been to reduce the Commons to 600 seats. The review is “a crucial democratic step, and Labour will engage fully and constructively in the consultation”, said Cat Smith, Labour’s shadow cabinet office minister – whose own Lancaster and Fleetwood constituency is due to become just Lancaster and, according to the commission, “significantly different”. She added: “But the Conservative government’s one-size-fits-all approach to the exact size of constituencies has made the Boundary Commission’s work much harder, and will inevitably lead to the break-up of historic community ties across the UK.”