Political parties don’t know where the boundaries are

In my last blog post, I explained the new service TheyWorkForYou offers to show you what constituency you will be in at the next general election. Now I’m going to show you why you shouldn’t use anything else.

The defintions of the boundaries for the forthcoming constituencies in England were originally published in The Parliamentary Constituencies (England) Order 2007 (SI 2007/1681), based on ward boundaries as they were on 12th April 2005. However, due to some local government changes since that date, The Parliamentary Constituencies (England) (Amendment) Order 2009 (SI 2009/698) was published changing the boundaries for four constituencies – Daventry, South Northamptonshire, Wells, and Somerton & Frome – to be based on the new council wards as they were on 3rd May 2007.

The forthcoming constituencies in Northern Ireland were defined in The Parliamentary Constituencies (Northern Ireland) Order 2008 (SI 2008/1486). In this, Derryaghy ward was split between two constituencies – Belfast West is given “that part of Derryaghy ward lying to the north of the Derryaghy and Lagmore townland boundary.”

All of which means that other sites that try to tell you what constituency you will be in at the election invariably get it wrong.

Both Labour and the Conservatives say that BA6 8NJ is in Wells at the next election, when it will be in Somerton & Frome. Both say that NN12 8NF will be in Daventry, when it will be in South Northamptonshire. I assume that both sites are using boundary data predating the Amendment Order from March 2009. The Conservatives also say that BT17 0XD will be in Lagan Valley when it will be in Belfast West; Labour simply say “Northern Ireland” for any Northern Irish postcode you provide.

The Liberal Democrats site currently returns no results for any postcode, which I assume is a bug 🙂

The current boundary between Belfast West and Lagan Valley.

The /current/ boundary between Belfast West and Lagan Valley. (Image produced from the Ordnance Survey electionmap service. Image reproduced with permission of Ordnance Survey and Land and Property Services)

The official election-maps.co.uk service (from where TheyWorkForYou gets its boundary maps) returns the correct results for BA6 8NJ and NN12 8NF, but doesn’t have future boundaries for Northern Ireland. It’s not clear that it doesn’t, as searching for Lagan Valley with “future boundaries” selected returns a result, but that result is the current boundary. This can be seen from the picture on the right – as is clear from the quote I gave above, everything within Derryaghy ward north of the Lagmore/Derryaghy boundary will be in Belfast West at the next election. Plus the site doesn’t work without JavaScript.

TheyWorkForYou’s “constituency at the next election” service gives BA6 8NJ in Somerton & Frome, NN12 8NF in South Northamptonshire, and BT17 0XD in Belfast West. There is enough confusion with the changes to boundaries for everywhere except Scotland, that it is somewhat frustrating to have it compounded by sites giving incorrect information. The lack of any official service also doesn’t help.


  1. Postcode searches are now restored on http://www.libdems.org.uk so you can see that we return your examples correctly for new constituencies. (The exception is the Belfast West postcode as we don’t stand candidates in Northern Ireland.)

    Very pleased to see that TWFY now offers new boundary lookup though (you may remember my request for it in the past). It’s been frustrating not having a commercial source, let alone a free one. Good work!

  2. I did assume it was just a bug 🙂 Glad to hear it’s fixed. I still think you could give a nicer message for a Northern Ireland postcode than “Sorry, we couldn’t find a constituency matching your postcode” – your map has the whole UK, and even has a hover/link on Northern Ireland that doesn’t go anywhere. Simply saying you don’t stand candidates in Northern Ireland would at least tell people who might not know that.

  3. The key line in your piece here, Matthew, is the final line: ‘The lack of any official service also doesn’t help.’ For something so fundamental as this, we shouldn’t have to rely on a charity to provide it.

    PS The situation of the LibDems’ site re Northern Ireland is made worse by the inclusion of ‘N. Ireland’ in the page footer – an external link to their sister party, Alliance, but presented in exactly the same format as the Scottish and Welsh LibDems. As an Ulsterman, I’m used to general ignorance of such matters. But who built the new LibDem site? Ah yes, a Belfast agency. ??

  4. Yes, I guessed that 🙂 And as I said, I tried it and it appears to be working fine. What postcode did you try that makes you think it wasn’t working or gave an incorrect result?

  5. We the unwashed masses are very eternally grateful that you’ve put all the time and effort you have into compiling a correct and proper postcode-constituency lookup. Now can we have a simple denormalized CSV of all of them rather than having to go through the online api?

  6. Ric: I’m afraid not, as supplying a list of all postcodes would clearly break our licence under which we have access to a postcode database.