There are a small number of apps that are specific to the UK, and I thought it might be useful to pull together a list of those which VoiceOver users find particularly good.
A couple that I regularly use are:
NextBuses: great if you are a regular user of buses. The developer has paid specific attention to making this accessible, and it shows!
TV-Guide UK (free): a very accessible way to browse what's on television.
I would be very interested in hearing any other recommendations.