How to correctly match UK postcodes by prefix?

Question

I have a number of restaurants who all deliver to certain postcode areas in London, for example:

• EC1
• WC1
• WC2<

Answer 1

The below graphic explains the format of UK postcodes:

Source: https://www.getthedata.com/postcode (My site) So you can see that you need Outcode which given your requirement (given a full postcode with no space) is simply your space-free postcode minus the last three characters.

In PHP this would be:

$outcode = substr($postcode_no_space, 0, -3)

Of course this does not help with validating the postcode, but as you point out in your comments the question is not about validation.