Media playback is unsupported on your device Media caption Watch Colin Welland's acceptance speech after being awarded an Oscar for best original screenplay for Chariots of Fire in 1982

Oscar-winning writer and actor Colin Welland has died aged 81 after suffering from Alzheimer's disease, his family has announced.

Welland won an Oscar in 1982 for best original screenplay for writing the film Chariots of Fire, about two athletes at the 1924 Olympic Games.

He famously used his acceptance speech to declare: "The British are coming."

As an actor, he won a Bafta for playing the sympathetic English teacher Mr Farthing in Ken Loach's Kes in 1969.

Image copyright AP Image caption Colin Welland (left) accepted his Oscar for best screenplay from author Jerzy Kosinski

Chariots of Fire producer David Puttnam said Welland was "an unswervingly good man; a fine actor, and a seriously gifted screenwriter".

Lord Puttnam continued: "These gifts not only brought him most of the accolades TV and cinema can ever offer, but cemented the careers of everyone who rode on the back of his Chariots of Fire.

"The depth of his feelings, and sense of identity with the people he wrote about was achingly real."

Nigel Havers, who appeared in the film, told BBC News: "When he said the British were coming, it was ironic. It was a joke. That was his sense of humour. But people took him seriously.

"I remember him being great fun with a great sense of humour and a very honest man. He had a tremendous honesty about everything he wrote. I'm just very surprised he never made more films in Hollywood. It's a great loss to us all."

Image caption Welland started his TV acting career in Z Cars in the 1960s

Image caption Welland (left) starred in Dennis Potter's Blue Remembered Hills

Welland found fame in the early 1960s when he played PC David Graham in TV police serial Z Cars.

His Z Cars co-star Brian Blessed paid tribute, describing Welland as "a great writer and a very natural actor".

Blessed said: "He had a tremendous ability for writing. He could write anything, any style.

"And of course he was marvellous in [Dennis] Potter's play Blue Remembered Hills, playing a little tiny boy. An amazing performance. He was very versatile and immensely clever."

Fellow actor David Morrissey tweeted: "Colin Welland RIP. Such a great actor and writer. Kes is my all-time favourite film and he was so wonderful in it. So sad."

Image copyright PA Image caption Welland won Bafta awards for writing and acting in the same year

Welland was a teacher in Leigh, Lancashire, before deciding to pursue his ambition to act at the age of 26.

"I was going to get married and I thought, if I get married I will lose my opportunities, because responsibilities follow marriage," he said.

He joined Manchester's Library Theatre and had a three-week stint as a BBC newsreader before joining Z Cars.

He went on to successfully combine acting and writing, and scooped a Bafta TV Award for writing TV plays in 1971. That year, he also won the Bafta film award for best supporting actor for Kes.

'The individual against the system'

His film writing credits also included 1979's Yanks, which starred Vanessa Redgrave and Richard Gere, and 1985's Twice in a Lifetime.

As an actor, he played a vicar in Dustin Hoffman's 1971 thriller Straw Dogs and appeared in both the TV series and the big screen version of crime drama The Sweeney.

Also on TV, he was an overgrown schoolboy in Dennis Potter's 1979 play Blue Remembered Hills and appeared with Roy Kinnear in 1980s sitcom Cowboys, about incompetent builders.

Most of his own plays were set in the north of England and "usually champion the individual against the system", he told BBC Radio 4's Desert Island Discs in 1973.

"I usually find that it's one man's effort to break through what is usually expected of an individual."

Colin Welland's 1982 Oscars acceptance speech

"What you've done for the British film industry... I'd just like to thank David Puttnam for having the wisdom to ask me to write it in the first place. Hugh Hudson for respecting me and my script, which is a very hard thing to find in our business, as you know.

"All the actors for getting fit enough to appear like Olympic athletes and to British television, where I learned my craft. I'd like to finish with a word of warning. You may have started something - the British are coming."

After the success of Chariots of Fire, he tried to make a film titled Rocket about George and Robert Stephenson, the father and son who developed rail travel.

"I took Rocket to America immediately after Chariots of Fire had come out," he wrote in The Guardian in 2001.

"'We want another Chariots of Fire,' I was told. 'It is another Chariots of Fire,' I said. 'Men against the establishment.

"'Robert Stephenson couldn't read and write, yet he was the greatest engineer of his generation. He had the world against him, yet he fought through. It is another Chariots of Fire.' But they wanted another film about runners."

In a statement released via his literary agent Anthony Jones on Tuesday, his family said: "Colin will be desperately missed by his family and friends.

"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."