Hi,
Here are a few from a british top 100 list at
http://www.britishpictures.com/:
1 The Third Man (1949, Carol Reed)
2 Brief Encounter (1945, David Lean)
3 Lawrence of Arabia (1962, David Lean)
4 The 39 Steps (1935, Alfred Hitchcock)
5 Great Expectations (1946, David Lean)
6 Kind Hearts and Coronets (1949, Robert Hamer)
7 Kes (1969 Ken Loach)
8 Don't Look Now (1973, Nicolas Roeg)
9 The Red Shoes (1948, Michael Powell, Emeric Pressburger)
10 Trainspotting (1996, Danny Boyle)
11 The Bridge on the River Kwai (1957, David Lean)
12 If... (1968, Lindsay Anderson)
13 The Ladykillers (1955, Alexander Mackendrick)
14 Saturday Night and Sunday Morning (1960, Karel Reisz)
15 Brighton Rock (1947, John Boulting)
16 Get Carter (1971, Mike Hodges)
17 The Lavender Hill Mob (1951, Charles Crichton)
18 Henry V (1944, Laurence Olivier)
19 Chariots of Fire (1981, Hugh Hudson)
20 A Matter of Life and Death (1946, Michael Powell, Emeric Pressburger)
21 The Long Good Friday (1980, John Mackenzie)
22 The Servant (1963, Joseph Losey)
23 Four Weddings and a Funeral (1994, Mike Newell)
24 Whisky Galore! (1949, Alexander Mackendrick)
25 The Full Monty (1997, Peter Cattaneo)
For 75 more great british movies, here is the link to the site I got these from:
http://www.britishpictures.com/articles/BFI100.htm
Good luck!
Hope this has helped.