The Oscar-winning writer and actor Colin Welland has died aged 81, his family has announced.

The Lancashire-born father of four, who starred in Kes and Z Cars, won his Academy Award for the screenplay of Chariots of Fire in 1981, famously waving his statue and announcing in his acceptance speech: “The British are coming!”

His family said in a statement that he had Alzheimer’s disease for several years but died peacefully in his sleep.

“Colin will be desperately missed by his family and friends,” the statement read. “Alzheimer’s is a cruel illness and there have been difficult times, but in the end Colin died peacefully in his sleep. We are proud of Colin’s many achievements during his life, but most of all he will be missed as a loving and generous friend, husband, father and granddad.”

David Bradley and Colin Welland in Kes Photograph: Allstar/WOODALL FILMS/Sportsphoto Ltd./Allstar

Welland gained fame with a role in BBC police drama Z Cars before starring in 1969’s Kes as English teacher Mr Farthing and in 1971 thriller Straw Dogs. He also continued to work on the small screen with roles in The Sweeney and Trial & Retribution.

His focus soon switched to writing and as well as his Oscar-winning script for Chariots of Fire, his credits included Yanks, starring Richard Gere, and A Dry White Season, with Donald Sutherland. He also won a Bafta in 1972 for best single television play for Play for Today: Kisses at Fifty.

It was an American adaptation of that play that led to his famous “The British are coming” call. At the time of the 1982 Oscars, he was living in a small town in Washington state and whenever he would frequent a local bar, the locals would call out the infamous phrase.

“The reaction to Chariots of Fire from America was: who wants a story about two athletes from 1924?” he wrote in an article for the Guardian in 2001. “When we showed it at Twickenham, a Hollywood producer left after 10 minutes, came back at the end and said that they wouldn’t have anything to do with it. When it won four Oscars, I don’t know where he hid himself.”

His last acting credit was in a 1998 episode of TV drama Bramwell and his last screenplay was the 1994 family film War of the Buttons.