LONDON: Richard Griffiths was one of the great British stage actors of his generation, a heavy man with a light touch, whether in Shakespeare or Neil Simon. But for millions of movie fans, he will always be grumpy Uncle Vernon, the least magical of characters in the fantastical Harry Potter movies.

Griffiths died Thursday from complications following heart surgery. He was 65.

Harry Potter star Daniel Radcliffe paid tribute to the actor Friday, saying that “any room he walked into was made twice as funny and twice as clever just by his presence.”

Griffiths won a Tony Award for The History Boys and appeared in dozens of movies and TV shows. But he will be most widely remembered as two contrasting uncles — Harry Potter’s Uncle Vernon Dursley and Uncle Monty in cult film Withnail and I.

Griffiths was among a huge roster of British acting talent to appear in the Harry Potter series of films released between 2001 and 2011.

His role, as the grudging, magic-fearing guardian of orphaned wizard Harry, was small but pivotal. Griffiths once said he liked playing Uncle Vernon “because that gives me a license to be horrible to kids.”

But Radcliffe recalled Griffiths’ kindness to the young star.

“Richard was by my side during two of the most important moments of my career,” said Radcliffe, who in 2007 starred with Griffiths in a London and Broadway production of Equus.

“In August 2000, before official production had even begun on Potter, we filmed a shot outside the Dursleys’, which was my first ever shot as Harry. I was nervous, and he made me feel at ease.

Earlier, Griffiths was the louche, lecherous Uncle Monty to Richard E. Grant’s character Withnail in Withnail and I, a low-budget British comedy about two out-of-work actors that has become a cult classic. Years after its 1987 release, Griffiths said people would regularly shout Monty’s most famous lines at him in the street.