Parliamentary boundary changes

Parliamentary boundary changes appear to be a source of confusion to many people and organisations. The facts are quite simple – parliamentary boundary changes, proposed by the various Boundary Commissions, do not take effect until the next general election. Until then, your MP remains whoever they have been, no matter what literature you may get through your letter box, or what anyone may tell you.

As one example, take Birmingham City Council. Their page on constituencies and wards correctly states that Birmingham is divided into eleven parliamentary constituencies, but then goes on to list only ten – they are listing the new constituencies which do not yet exist, as Birmingham is losing one constituency at the next election. It appears that they have organised themselves along the new boundaries in advance – which is fine, but this doesn’t affect current Parliamentary representation, and so they should explain this clearly, as otherwise members of the public get confused (and blame us for giving them the “wrong” MP, when we haven’t done so). As you can see from the maps above (which highlight Birmingham, Hall Green), the constituencies will be changing their boundaries quite a bit, and we have had reports of people receiving letters from candidates in the next election who are MPs of different neighbouring constituencies, simply referring to themselves as an MP, which is a great source of confusion.

An inhabitant of St Josephs Avenue, Birmingham (behind the Royal Orthopaedic Hospital), which is currently within the Selly Oak parliamentary constituency (red), and the Northfield ward of Birmingham City Council (green), would, on looking at Birmingham City Council’s website, assume they’re in a parliamentary constituency called Northfield. Northfield is currently the constituency to the west of Selly Oak; at the next election, its boundary with Selly Oak will change to the blue line, at which point St Josephs Avenue will be in the Northfield constituency. But not until then.

Map of Streatham constituency at next election

As another example (chosen purely as it has come up in user support), the Labour candidate’s website for Streatham had a page about the constituency – obviously you would expect a candidate to be talking about the future constituency, but would it hurt to add some explanation that Streatham is currently a slightly different shape?

Boundaries of different things are all independent – if a ward boundary moves due to some local issue, the corresponding Parliamentary boundary does not necessarily change with it (probably not, in fact). So when Birmingham changed its ward boundaries back in 2003, they became out of sync with the Parliamentary constituencies. From the next election, things will be more in sync as the new Parliamentary boundaries are based on more recent ward boundaries, but this will again separate over time. All we can do is always clearly explain the current situation, and ask that others do the same.


  1. My MP (Kate Hoey) seems to have stopped writing back to people in the part of her constituency that is joining Dulwich & Norwood. I’m guessing the WriteToThem stats arent available to test that kind of thing though?

  2. If we get the future Parliamentary boundaries into our system, as we’ll have to do at some point, then we would be able to run that sort of test on the data we hold, comparing the response rate for postcodes moving constituency to those remaining…

  3. A beautiful illustration of the problem we have in the UK, with boundary policy. Too many changes – for very little reward, and too many inconsistencies: where I used to live, in Staines, we were in Middlesex for postal purposes, Surrey for policing, London for (most of the) buses – although not a London borough, hence no political say… etc etc.

    If all the parties are promising to free up their data post-election, we’re in for a collective shock when we realise the data geographies don’t match up.

    I think there’s a strong case for picking a set of coherent, cascading boundaries, and pledging to stick to them – not for five or ten years, but more like 50.

  4. What would you do to deal with population migration? Over 50 years, I could foresee very large changes in representation. I don’t have any issue with the current 8-12 year cycle – that seems about right actually – as long as the data is made available freely for people to be able to know where they are (quite important in a democracy!), which it isn’t anywhere near as much as it could be.