This refers to the 1965 Bermuda Bowl World Championship when there was an accusation that the British pair, Terence Reese and Boris Schapiro, cheated by transmitting information regarding the length of their heart suits by finger signals.
Although at the time the World Bridge Federation executive committee found Reese and Schapiro guilty, a subsequent thorough independent enquiry headed by Sir John Foster QC and General Lord Bourne found that the charges were unfounded. Arguments for both sides can be read in the books The Story of an Accusation by Terence Reese and The Great Bridge Scandal by Alan Truscott.