Forstater, who produced the 1975 movie, sued the surviving members of the Monty Python comedy troupe, claiming he was underpaid royalties since the hit stage musical's premiere in 2005, the BBC said.
He estimated he was entitled to about $300,000 and a High Court determined Friday he was right.
Eric Idle, Michael Palin and Terry Jones -- three of the stars of the cult film -- testified at the trial. John Cleese and Terry Gilliam are the remaining survivors of the group. Python member Graham Chapman died in 1989.