William Hartnell was the original Doctor Who

Former cast and crew members joined family members to watch the three plaques be unveiled on Sunday.

Stars who played the assistants to each of the Doctors were on hand to pay tribute to their former co-stars.

Carol Anne Ford acted with Hartnell between 1963-66, Frazer Hines appeared with Troughton from 1966-69, and Elisabeth Sladen starred with Pertwee from 1970-74.

Fans from Canada and the United States were expected to fly in to attend the event.

Hartnell's granddaughter Jessica Carney was due to be joined by Pertwee's widow Ingeborg, son Sean and cousin, Dad's Army star Bill.

The Doctors fought creatures like Daleks and Cybermen

An auction of memorabilia at a charity lunch followed the ceremony.

Hartnell, Troughton and Pertwee were the first of eight Time Lords, and established the series as the UK's favourite home-grown sci-fi series.

The Doctor, who travelled with his assistant in the Tardis, was a fixture in TV schedules until the 1980s.

It has been revived for one-off specials, and a new series of internet-only adventures recently went online.

Hartnell died after years of ill health in 1975, while Troughton died in 1987 and Pertwee died of a heart attack in 1996.