Locations This is one of my favourite films - although I agree Peter Sellers does not steal the show (for once), its the whole cast and their interaction which makes this film so special.
Lionel Jeffries gives a brilliant performance as an inept policeman and Bernard Cribbins role as 'Pearly Gates' gang-lord rival is superb. The plot is well covered on this site, but I would like to add that the robbery on the security van was filmed in Mill Rd, Uxbridge (by the canal bridge - the shop&pub are still there) and I think the airfield was Denham (again nr. Uxbridge).
A brilliant film - They just don't make 'em like that anymore!
On a similar thread I would recommend Norman Wisdom in 'On the Beat'- one of his best performances in my opinion, and Sellers again in 'Two-way stretch' if you're looking for a good laugh.