Oh no, I broke the golden rule and started mucking around with Greasemonkey, which was a mistake, as I have now wasted this entire evening. Anyway, it is fun to play with custom code in webpages, and after basically looking at other people’s code I’ve come up with a simple little widget – it turns any UK postcode in a page (which is not already inside a hyperlink) into a hyperlink to the relevant Google Maps map for the area – e.g. SW1A 2AA becomes SW1A 2AA. Want to try? Install it from here (you must have Greasemonkey installed first, obviously – download it here). Enjoy. Lots of it is derived from others’ work – credits are in the source code. Any bugs, report in the comments below.