Nicholas Courtney, the actor known to Doctor Who fans for many years for his role as The Brigadier, has died at the age of 81, his biographer said.

The actor starred in dozens of episodes during his Doctor Who career and played opposite five Doctors. He was a key figure in the Time Lord’s adventures during Jon Pertwee’s run as The Doctor, but popped up occasionally opposite other stars.

Nicholas died on Tuesday evening after a long battle with cancer, according to Michael McManus, who worked with him on his two memoirs. He was in a hospice in Hampstead, north-west London, with his wife Karen at his side.

UNIT chief Brigadier Alistair Lethbridge-Stewart first appeared in the late 1960s. After an absence of many years, when the show was axed for a lengthy period, he reprised the role – this time as Sir Alistair – in 2008 for spin-off children’s series The Sarah Jane Adventures.

The Egypt-born star went to drama school after his national service and went into repertory theatre. In the 1960s he picked up a string of TV roles including appearances in The Saint, The Champions and The Avengers. Later roles included appearances in shows such as All Creatures Great And Small, Yes, Prime Minister and Only Fools And Horses.

His first Doctor Who appearance was as a “space security agent”, but he went on to land a further role as a Colonel, later promoted to Brigadier in a story called The Invasion.

Among those to pay tribute were actor and Doctor Who writer Mark Gatiss who said he was “desperately sad” to hear of the death, adding: “A childhood hero and the sweetest of gentlemen. Splendid chap. All of him.”

Impressionist and Doctor Who buff Jon Culshaw said: “Nicholas Courtney will be very much missed. A brilliant actor and warm, charming man” while film director Edgar Wright said: “He was a true gent.”

Known for his suave appearance with a well-groomed moustache as The Brigadier, his association with Doctor Who continued when he became honorary president of the Doctor Who Appreciation Society from 1997.

Twice-married Nicholas leaves two children, Philip and Bella, from his first marriage.