Sir Peter played Belgian detective Hercule Poirot in five films

Whether playing a French cafe owner, a slave trader or Agatha Christie detective, his commanding screen prescence was hard to ignore.

"He can be thought of as a more comedic Orson Welles," said film critic Quentin Cooper.

Derek Malcolm, former film critic at The Guardian, said Sir Peter had been an A-list for almost 30 years.

Sir Peter began his stage career aged 17, performing sketches he had written in the 1939 revue show Late Joys while training at London Theatre Studio.

After an uncredited cameo in 1942's Let the People Sing, Sir Peter employed his linguistic skills as the French cafe owner Rispoli in The Way Ahead.

'Terrified'

He would go on to write and star in Vice Versa, Private Angelo, Lady L and Romanoff and Juliet, and directed himself in an ambitious adaptation of Billy Budd. He continued to shine in films directed by others, notching up 87 cinema and TV film credits in addition to theatrical work.

"I am still terrified of the amount of lines which must be learnt," Sir Peter told Lady magazine in 2002. "I have twice played King Lear and still have no idea how the task is achieved."

Ustinov won an Oscar for his portrayal of a slave trader in Spartacus

His riveting performance as emperor Nero in 1951's Quo Vadis earned him an Oscar nomination, as his character goes spectacularly mad and burns Rome.

His equally intense portrayal of slave trader Lentulus Brutus in Spartacus earned him the best supporting actor Oscar nine years later.

Demonstrating his versatility, Sir Peter took his second Oscar as the bumbling Arthur Simon Simpson in 1964's comedy thriller Topkapi.

Depth

But accolades did not breed snobbery in Sir Peter and he continued to appear on US television in such roles as King George and Dr Samuel Johnson. He also relished a cameo appearance in The Muppet Show in 1976.

Despite his broad range of acting assignments, Sir Peter is perhaps best known for playing Agatha Christie's playful detective Hercule Poirot in five films, beginning with 1978's Death on the Nile.

He played Hnup Wan in Disney's One of our Dinosaurs is Missing

"Poirot would be a very easy character to get a laugh out of, but Ustinov made him somebody with intelligence and drive whom the audience sympathised with," said Quentin Cooper.

"There was always a sense of depth to his characters. There was both a passion and a compassion."

In his later career Sir Peter voiced characters on cartoon series Dr Snuggles with the same relish that he played a professor in 1992's emotive movie Lorenzo's Oil.

"He worked across the different eras and genres with ease," said Mr Cooper.