Roger More in "Ffolkes" from 1979 (A.K.A. North Sea Hijack). This movie also has two time Felix Lighter actor David Hedison in it too.

Moore stars as an eccentric British adventurer with a disdain for women and a fondness for cats. Moore leads a small underwater commando group that does the occasional favor for Lloyds of London. The British government has a problem. Two oil rigs in the North Sea and a Norwegian Cargo Freighter are being held to ransom. A terrorist group has overrun the freighter and has both it and the two rigs fitted with booby trapped bombs. The economic, environmental and human cost if the British refuse the ransom could be astronomical. Unwilling to negotiate with hostages the government decides to contact Lloyds with a view to using their private specialized methods for dealing with problems. This is where Moore's character Ffolkes comes in. With a truly exceptional cast including James Mason, Anthony Perkins and David Hedison "North Sea Hijack" (aka "Ffolkes") is an enjoyable romp that is high on action and good humor.