This Hitchcock classic is on an extended run at BFI Southbank. See here for details.
Chicago Reader review of To Catch A Thief:
'Cary Grant is a retired cat burglar on the Riviera and Grace Kelly is the spoiled American rich girl who seems to have the perpetual hots for him, in Alfred Hitchcock's fluffy 1955 exercise in light comedy, minimal mystery, and good-natured eroticism (the fireworks scene is a classic). Jessie Royce Landis (North by Northwest) is delightful as Kelly's clearheaded mother (she and Grant were born the same year, by the way), and John Williams gives expert support as usual.'
Here is the trailer.