Add facility to split postcodes over two constituences

[Deborah-mySoc]

At the moment people whose postcodes straddle a boundary may well find themselves given the wrong representatives, and the only workaround is for them to use a nearby postcode in the correct ward which is not ideal.

[MyfanwyNixon]

I've had a few emails about this.

Most recently:

 Entering post code doesn't work where roads are split
 between two boroughs I've found. e.g. SW16 5QW where Nos 1 to
 39 are in Norbury & comes under Croydon, but your web site only
 directs to Merton for this code.

 I see NSW web site has an additional option to enter more
 details to overcome such situations, so it would be extremely
 helpful if  yours could do something similar. I appreciate this
 may entail checking with respective boroughs to establish where
 else this applies, but at least enquirers (otherwise unaware)
 would not  be mislead that might adversely reflect on what you
 are trying to do.

 For me it also means I can no longer use auto links in campaign
 messages I receive, because they evidently use a similar source
 for re-directing a message to my representative, sending it to
 wrong MP.

 I am also raising this issue with my (correct) MP to see if the
 post code can be changed wherever necessary.

[MyfanwyNixon]

19th Dec 2013: I have received a request from Change.org to write to my MP using your service. Putting in my post code gives my MP as Mark Hunter, Cheadle constituency which is not correct. My MP is Andrew Stunell, Hazel Grove constituency. The dividing boundary between the two constituencies at my postcode SK2 7LD falls on the centre line of Dialstone Lane and the postcode straddles both sides of the street. My side of the street falls in the Hazel Grove constituency. Your organisation is not the only one that contains this error and it does not help my efforts to add my input to campaigns that ask me to contact my MP.

[MyfanwyNixon]

10th July 2014:

My postcode L149NH incorrectly takes me to the
 Knowsley ward for MP George Howarth, when infact my ward is the
 West Derby ward in Liverpool: Stephen Twigg.

[MyfanwyNixon]

16th September 2013:

  SW16 5QW directs to representatives, & MP for Merton
 e.g.Siobhain.Mcdonagh.

 Fortunately I know my MP is Steeve Reed, but it's not possible
 to amend the information on your site to use the links
 provided, & is especially misleading to new residents without
 my knowledge.

[MyfanwyNixon]

13/9/13:

I have noticed an error on your website concerning this post code NG8 2PD. The odd numbers on this street up to number 25 are in the constituency of Broxtowe and the remaining even and odd numbers fall within Lillian Greenwood MP’s constituency of Nottingham South.

[MyfanwyNixon]

7/5/13:

The postcode WS5 4DU refers to Laburnum Road, of which numbers 1-3 are within my constituency. The rest of the road, which shares the same postcode, is in the West Bromwich East Constituency. Write To Them only lists this postcode as being in West Bromwich East even though part of this postcode area is within Walsall South.

I would be grateful if you could update your records to indicate that this postcode covers both Walsall South and West Bromwich East.

[MyfanwyNixon]

22/03/13 My postcode is TD3 6LG and my MSP is John Lamont. You still have my MSP as Christine Grahame.

[MyfanwyNixon]

So - if we're quantifying how many users it affects, I guess it's a small percentage - as you can see above, these are 7 emails within the space of about 19 months.

Although - there will be some users who don't know that we are delivering the wrong results for them.

[jacksonj04]

I'm really not sure how we'd present this to a user, given we'd get things like "Your postcode crosses a constituency boundary; if you're on the west side of {road} your MP is {foo}, if you're on the east side of {road} your MP is {bar}". Coming up with all the cases and a suitable differentiator is not an easy or short job, although would be an interesting dataset.

[dracos]

"I'm really not sure how we'd present this to a user" - with access to a dataset such as http://www.ordnancesurvey.co.uk/business-and-government/products/address-point.html you would, given a postcode, ask them to select their address, and as you then know the location of that address, be able to work out which side it is in.

[MyfanwyNixon]

" My postcode is split between districts, with two houses in the Canterbury district and two in the Shepway district. I am in Canterbury, but your website incorrectly states that I am in Shepway and gives me contact details accordingly. I think it would be better if you identified postcodes that are or may be split in this way, and provided both sets of data so that people could choose the right answers for themselves.

 Although of course I am aware that this is a free service and
 you don't actually have any particular obligation to me."

[MyfanwyNixon]

Further, from the last commenter: "If you have a data set of ward boundaries treated as polygons, maybe you could just run a one-off geo-search to find all postcode centres that are within 100m of a boundary, and treat all of those as suspicious. (Or perhaps 200m, but 100m would work fine for my postcode). But I'm not sure if such a data set exists, at least for free. (I spent nine years working at Rightmove, and was involved with quite a lot of the geo-search and postcode/location mapping work there, so I understand how difficult these things can be.)"

[MyfanwyNixon]

"Whenever I use a website which offers to tell me my constituency it always only gives me Coventry North West. I know that this is wrong and also know my MP's and councillors' email addresses, but it is still irritating and may be misleading to my neighbours who don't know which constituency they are in. Is there anything at all you can do about this - it can't be the only postcode in the country to which this issue applies."

[MyfanwyNixon]

"Under your system of write to them, my post code seems to throw up Camberwell and Harriet Harman as MP rather than Vicky something....

Most of SE15 is Southwark. But some of SE15 is Lewishm. I cannot use your format to write to Councillors or my MP."

[MyfanwyNixon]

"This looks like a really good site, but like other places I’ve tried you give me the wrong set of people for my post code. I am on a boundary I know, so it is harder. My post code is WS15 4JJ, but my MP is Michael Fabricant, and the council I vote for is Lichfield not Cannock. I am trying to find out my MEP but cannot trust your list as all that I do know is wrong for me,"

[MyfanwyNixon]

"I am a Councillor in Larkswood ward in LB Waltham Forest. A resident contacted me because the look-up on your site told her I was her Councillor, but I’m not. Her address is [...] E4 9DU. "

[dracos]

E4 9DU is 63-117 Larkswood road, which is all within Larkswood ward.

[MyfanwyNixon]

One from HU6 8QT.

[dracos]

HU6 8QT is 1-12 Moorbeck Close, Hull, which is fully contained within University Ward, Kingston upon Hull.

[MyfanwyNixon]

Just to inform you that because I live on the edge of the parliamentary boundary I am unable to use your site to communicate with my MP unless I use a false postcode (I use the one for the road behind me, or just up the road towards Mangotsfield) but then use my proper street address. This is somewhat annoying. The residents of number 59 are in a different ward to me.

[MyfanwyNixon]

You give the MP for TN21 8QB as Huw Merriman but unfirtunately he is only one of them! The other is Nusrat Ghani ... the postcode is split between two constituencies

[MyfanwyNixon]

My Postcode is SY11 1TB and on 38degrees site and your own claims I am in Oswestry West wheras I'm actually in Oswestry South. This makes it difficult to use either site to contact my Councillor.

[MyfanwyNixon]

WR14 4EL

[mhl]

@symroe wrote a blog post on this topic, including a list of the postcodes that are split across one or more councils: https://democracyclub.org.uk/blog/2017/03/20/4314-times-when-postcodes-arent-good-enough/

We could use that list to at least warn people that we might not have selected the right council for them, even if we can't provide better help without AddressBase. (We presumaly need to worry about postcodes being split across other boundary types too, but this could help some users anyway...)

The script that generates that CSV file could be updated to also include details of which 2 or 3 councils the user's postcode might be in, so we could offer a switch for people who do know which council they're in.

[MyfanwyNixon]

Given this, could you show a small map like the one in the article and ask users to click where their house is?

[symroe]

That's a great idea! No need for AddressBase that way!

Wouldn't be very accessible, but you could fall back to a list of authorities.

[dracos]

How would we know for which postcodes to show this map? I imagine if we show it for everyone, they'll then be annoyed when we haven't prefilled their address…!

[abibroom]

DE22 4NH is another affected postcode.

[symroe]

DE22 4NH is in the list I made on the gist linked to in the blog post above :)

[MyfanwyNixon]

There's also a suggestion from a user on https://github.com/mysociety/theyworkforyou/issues/197:

I'm in the same constituency as everybody else in XX0 0??. For unknown postcodes you could try removing the last two letters of the postcode and check if all the postcodes with that prefix are in the same constituency, and if so use that constituency. Just an idea."

[symroe]

We updated our gist over the election with a new file with one line per (split) postcode and the GSS code of the local authorities that it's split between.

https://gist.github.com/symroe/5d2045220bdb62d50c67378f2eb31a57#file-one_line_per_postcode-csv

[MyfanwyNixon]

We got a couple more complaints about this today; don't know if they're worth recording any more, but maybe it's good to keep count of how many people are vocal about it, also to be aware of potential reputational issues.