Shadow Run (1998)

Haskell (Sir Michael Caine) is assigned a job by his boss, the aristocratic Landon-Higgins (James Fox), to highjack a high-security van in broad daylight while it's in the shadow run (out of radio contact with the main security firm). He assembles a team to carry out the heist, but things don't go according to plan, and Haskell begins to think his boss might be double crossing him. Add to this, a teenage boarding school pupil has already witnessed some of the meetings of the team and Haskell's in real trouble.