open google maps to bus directions
From MapKiWiki:
dirflg Route type:
- dirflg=h - Switches on "Avoid Highways" route finding mode.
- dirflg=t - Switches on "Avoid Tolls" route finding mode.
- dirflg=r - Switches on "Public Transit" - only works in some areas.
- dirflg=w - Switches to walking directions - still in beta.
- dirflg=d - Switches to driving directions.
So your URL:
NSString* urlString = @"http://maps.google.com/maps?saddr=London+UK&daddr=Birmingham+UK";
Becomes:
NSString* urlString = @"http://maps.google.com/maps?saddr=London+UK&daddr=Birmingham+UK&dirflg=r";
N.B. The data supporting public transit route types are not always available. I tried the area you used in your sample (London, Birmingham) and found it was not supported.