Twenty-five years have now passed since the first Harry Potter film and, with the HBO reboot due out this Christmas, Warner Bros is ramping up the celebrations. Key among them is the unveiling of a new feature at the studio tour showcasing key moments, costumes and props from Harry Potter and the Philosopher’s Stone.

And this is why Mark Williams is now taking your questions – although, as Potter purists will know, his character doesn’t actually appear in the first film. Arthur Weasley does, however, play a pretty big role in the other seven movies, so let’s muggle through regardless.

In the movies, Williams plays the ministry of magic employee, husband to Julie Walters’ Molly Weasley and father of Ron, Ginny, Fred, George, Percy, Charlie and Bill – a role for which he had to dye his hair red.

“I turned into a fuzzy-haired ginger person,” he said in 2005, prompting Stephen Fry to ask him if the move was “for professional or sexual reasons?”

Williams will be answering your queries about all things Potter, as well as about his career to date, from his early work with the Royal Shakespeare Company and National Theatre in England to his breakthrough on The Fast Show in the 1990s – his most famous character, which presumably still makes clothes shopping nightmarish.

Of the slight lethargy at the start of his career, Williams, now 66, said, “I think it took longer for me to succeed because I’ve got a face like the corner of a crocodile handbag.”

Other movie credits include Stardust, 101 Dalmatians, The Borrowers, Shakespeare in Love, A Cock and Bulk Story, Albert Nobbs and Aardman’s Early Man. On the small screen, meanwhile, he’s been on Red Dwarf, Doctor Who, Carrie & Barry, Bottom, Saxondale, as Mr Beebe in the 2007 adaptation of A Room With a View and the lead in 140 episodes of Father Brown (as well as making a cameo as the same holy man in Sister Boniface Mysteries). Two further series of the show have recently started filming.

He also presented quizshow The Link in 2014 and 2015, and has fronted four documentary series about the UK’s industrial history, which taught him, he said, that “the human experience is that we often rely too heavily on the wrong things. The Victorians relied too heavily on coal, and they destroyed their cities and their children in the process. We’re no different today. We’ve been the same organism since Neolithic times.

“We think we’re cleverer than our forebears, but we’re not. We still bring up our children in the same haphazard way, and if there is more than one switch, we still don’t know which one turns the light on. The Americans spent millions of dollars trying to invent a pen that would work in space. Then the Russians went into orbit and found that the humble pencil worked perfectly well.”

Post your questions for Williams by noon BST on Monday 4 May and we’ll publish them in June in our regular reader interview series.