Robbie Coltrane was in pain ‘24 hours a day’ before his death, confirmed by his agent on Friday.

The Scottish actor, much-loved for portraying Hagrid in the Harry Potter series was pictured in a wheelchair after being left unable to work due to the need for a knee replacement with sources saying he had been in “constant pain for years”.

The 72-year-old, whose real name was Anthony Robert McMillan, died in hospital last week.

Despite his cause of death being unknown, osteoarthritis had completely destroyed his joints and left him in “horrible” pain.

He said: “I was fighting pain 24 hours a day when I was in National Treasure and Great Expectations. I had no cartilage in my knee. It was bone on bone.

He added: “It was just horrible. The relief from that pain since the operation and being able to sleep has changed my life.”

A source at the time said: “It’s left him unable to walk without any assistance and he’s been given a wheelchair while he waits to have a special surgical procedure in America to repair his joint.

“It’s hugely frustrating for him but he’s really hoping to be back on his feet after getting the operation.”

The star was interviewed as part of HBO's Harry Potter 20th Anniversary: Return To Hogwarts where he spoke of his legacy after playing the Hogwarts gamekeeper for so many years.

He said: "The legacy of the movies is that my children's generation will show it to their children, so you could be watching it in 50 years' time easy.

"I'll not be here sadly...but Hagrid will."