[Talk-GB] Tagging post towns and other addressing issues in the UK

Mark Goodge mark at good-stuff.co.uk
Mon Jan 28 20:56:03 UTC 2019

On 28/01/2019 18:50, Lester Caine wrote:
> On 28/01/2019 18:24, Will Phillips wrote:

>> There are certainly occasions when the street name is needed. For 
>> example, I recently surveyed a single postcode (DE72 2HP) containing 
>> two houses with the same house name, but different street names.  
>> Postcodes do sometimes cover two streets in rural areas. In these 
>> cases one might technically be a subsidiary street, but it's often not 
>> obvious which one.
> One could say that DE72 2HP is breaking Royal Mail's own rules, but it 
> is a rare exception to the rule, and often you find the street is 
> actually the secondary build reference rather than the street in the raw 
> data.

It isn't breaking a rule. The rule is that unit + street + postcode is 
the minimum required for an unambiguous postal address, as far as 
standard postcodes are concerned (large user postcodes are different, of 
course, but they, too, are a minority).

It is often the case that a postcode only covers a single street. But 
that's by no means universal, and it certainly isn't rare that it covers 
more than one.

Bear in mind that the whole point of the postcode system is to 
facilitate the delivery of post by Royal Mail. The final two characters 
of a postcode are the "walk" - literally, the smallest unit of the 
postman's round. And if there happens to be a pair of short streets, or 
a short street off a longer one, then they are often incorporated into 
the same walk. Topologically, this is the most common walk:


but this is a common one, too:


or this:


If the "vertical" section has a different name to the horizontal 
section, then it will typically also have duplicate numbering. Which 
means the street name is necessary to disambiguate.

I've just had a look at the Land Registry price paid data for my 
postcode area (WR), and there are 364 postcodes within it that are 
associated with more than one street name. That's a not a trivial or 
ignorable number, by any means, even if it is only a minority of 
postcodes. To guarantee a completely deliverable postal address, you 
need the street name.


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