When I was interning in London at an ad agency, I usually went out of the office for lunch.
Lunch was an hour and begun at 12:00, by 12:30 I was done eating. This left 30 minutes for photography in the City (I worked on Worship Street).

This photo was taken on Worship Street, London in 2009. I was 20 at the time and probably a few minutes late back from lunch.