This is an entertaining caper film given a little extra special something by Charles Grodin's deadpan voice-over. I'm alarmed to note from other comments that there's a version without the voice-over at large, wreaking untold damage and stopping the film gaining the cult rep it would surely otherwise enjoy. This is a desecration and those responsible must be hunted down with hounds.
Grodin is by turns funny and cool as hell as a small-time gem dealer forced to mount an ingenious large-scale heist against London's biggest diamond monopoly, the snobbish and deadly cabal at 11 Harrowhouse, enjoyably personified by an ice-cold John Gielgud and Peter Vaughan in full troll mode. James Mason is touching as the only decent man in the organisation and Trevor Howard on great form as the shady/barking-mad aristocrat who finances the robbery. Candice Bergen is adorable as Grodin's smart, beautiful, feisty paramour and accomplice.
In some ways the film is of its time (1974), mostly in a good way. In fact the only potentially laughable/winceable groovy-London moment is when Bergen casts the I-Ching while speeding along in her sports car; even that struck me as pretty cool actually. The schmaltzy piano-bar soundtrack works wonderfully, I think. London itself - buildings, vehicles, Pools-playing cockney security guards - looks gorgeously down-at-heel and I never watch this film without a twinge of nostalgia.
Catch it if it's ever on TV and you're in the mood for escapist fun - do make sure it's the version with the voice-over, though.
