He attended Uttoxeter Grammar School before joining Wolverhampton Repertory Theatre in what would prove to be a long stint in touring theatre. It was interrupted by war when he was called up to the army and saw service as an officer in Normandy and Belgium, an experience which he later described as 'terrifying.' He was transferred to the Far East, where he witnessed the liberation of allied prisoners of war from the appalling conditions in Singapore's Changi jail. 'It was a strange way, between the ages of eighteen and twenty four, to form a character. I think I was in a daze when I came back to Britain. It took me a while to come to terms with it.' While in Singapore, where he was commissioned in the Royal Corps of Signals, he had his first experience of radio work as a newscaster for Radio Malaya. At the end of the war the radio company offered him a three-year contract but he decided to rejoin his old rep company in England. He went back into the theatre playing dozens of minor roles and also married an up-and-coming young actress, Billie Whitelaw, in 1952. The marriage was not a success, although the couple stayed together for more than a decade. However, Peter found it impossible not to feel resentment at his wife's increasingly high profile as an actress as the decade progressed. 'As I got more and more work, Peter's difficulty in dealing with this was starting to show,' Whitelaw later wrote. In turn, she had a series of affairs.
He recalled Orton as 'a complete one-off. If I asked him about a line, he'd tell me it meant whatever I wanted it to mean.' Noticeably shady movie roles came playing Tallulah Bankhead's seedy handyman who meets a horrible end in the Gothic horror Fanatic (1965), his villainous roles in the spy thrillers The Naked Runner (1967 opposite Frank Sinatra) and The Man Outside (1967), a German thug in A Twist Of Sand (1968) and Sergeant Walker in the minor classic The Bofors Gun (1968). 'The great thing about [Sinatra] was that you had to stand up to him very quickly,' Peter recalled. 'If you did that, he respected you, otherwise he'd walk all over you.' Peter and Billie divorced in 1966 and Vaughan later married the actress Lilias Walker whom he had met when they both appeared in a play and who later had roles in a couple of picture with Peter, Malachi's Cove (1973) and Intimate Reflections (1974). During the 1970s he became a regular face on British TV. He excelled as Mister Paxton in the 1972 BBC adaptation of the MR James ghost story A Warning To The Curious. Two years later, he played the menacing criminal mastermind, Genial Harry Grout, in the BBC sitcom Porridge. It was a measure of the strength of his performance that many people assume he actually appeared in far more than the three episodes in which his character featured. 'I still get people saying: "Let you out, have they, Grouty?"' Vaughan told an interviewer earlier this year. 'I was in just three episodes and, of course, the feature film, so I have to thank the writers Dick Clement and Ian La Frenais for the fact I'm one of the characters people always remember when they talk about Porridge because Grouty is so prominent – even though I'm not there. Everybody's frightened to death of him, so they talked about him a lot and so it was a huge character but I didn't have to be there.' Later he played the authoritarian father of Robert Lindsay's girlfriend, Shirley, in the first two series of another classic BBC comedy, Citizen Smith.
His meticulous preparation for his roles became famous. When cast in Peter Flannery's BBC drama Our Friends In The North, as Christopher Eccleston's father Felix Hutchison who eventually develops dementia, Peter reportedly spent many hours in a home for people with Alzheimer's. 'One wants to be real above all things,' he later said. His performance won him a deserved BAFTA nomination for best actor. 'As Felix, over the course of four decades, I was able to go from a hard nut right the way through the various stages of that illness and it was really the first time it had been brought seriously to notice,' he said. 'It was a great privilege to play that part, it blazed the trail.' As he entered his eighth decade, the roles kept coming. He appeared in a number of films in the first decade of the new century including Death At A Funeral in 2007. At the age of ninety, he portrayed the sympathetic Maester Aemon of The Night's Watch in Game Of Thrones. His character was blind, an affliction which mirrored Peter's own failing sight.'People talk about Grouty but, good heavens, the fan mail I get from all over the world because of Game Of Thrones is enormous,' he told the Sunday Post. 'I've been so lucky with parts,' he told BBC Surrey recently in one of his last interviews in November. 'They talk about actors resting. The only time I have ever rested in my seventy seven years as an actor has been when I've wanted to. Lucky, lucky, lucky.'
And, on TV, in series as diverse as Tales From Soho, Time & The Conways, The Adventures Of Ben Gunn, Interpol Calling, Knight Errant Limited, Deadline Midnight, Three Live Wires, A Chance Of Thunder, the BBC's 1962 adaptation of Oliver Twist (as Bill Sykes), No Hiding Place, Hancock, Dimensions Of Fear, Rudolph Cartier's Stalingrad, Crane, The Saint, Knock On Any Door, Dixon Of Dock Green, Coronation Street. Quick Before They Catch Us, Our Man At St Mark's, Public Eye, Adam Adamant Lives!, Armchair Theatre, Haunted, Man In A Suitcase, Treasure Island (as Long John Silver), The Gold Robbers, Randall & Hopkirk (Deceased), Strange Report, The Wednesday Play, The Persuaders!, Thirty Minute Theatre, The Protectors, Fall Of Eagles, The Pallisers, The Sweeney, The Doombolt Chase, The Morecambe & Wise Show, The Crucible, Shelley, C.A.T.S Eyes, Sins, When We Are Married, Codename: Kyril, Chancer, Lovejoy, Nightingales, Dandelion Dead, Murder Most Horrid, Fatherland, The Choir, The Moonstone, The Tenth Kingdom, In Deep, Heartbeat, Casualty, Lark Rise To Candleford and Doc Martin. Peter is survived by his second wife, Lillias, their son David and twin step-daughters (including the actress Victoria Burton, the wife of Gregor Fisher).