The Great Fire is a lavish production, based on the true story of the fire which started in Thomas Farriner’s Pudding Lane bakery in 1666 and roared through London, destroying more than 13,000 houses in its wake.

Andrew Buchan is taking on one of the biggest roles in the series, as humble baker Farriner.

“Most of the ordinary working people lost everything they had in the fire,” said the actor.

“You realise just how much they suffered. You also wonder how on earth they managed to rebuild their lives after this disaster.”

With smoke filling the set, real fires raging, “manky teeth” and “muck and soot” inserted into his ears (“Everyone forgets the ears!”), The Great Fire wasn’t a glamorous job, but it’s one that will linger in Buchan’s memory for a long time.

“It’s point-blank terrifying,” he says. “We did a scene in a prison and filmed it in these dungeons. They pumped it full of smoke.

“You can’t see your right hand, you’ve got sweat pouring in your eyes and constant coughing.

“It’s possibly the hardest three days filming I’ve done.”

Buchan, who lives in Buckinghamshire with his wife Amy Nuttall, who played maid Ethel in Downton Abbey, found his small screen breakthrough in political drama Party Animals, before going on to take roles in Cranford and Garrow’s Law He went on to star in ITV’s runaway hit Broadchurch and weighty BBC drama The Honourable Woman – but now he is craving a role of a lighter kind.

“Having done a good nine years of darkness, I’m ready for comedy” says Buchan, who studied Modern Languages at Durham University before learning his craft at the Royal Academy For Dramatic Art.

He is pleased with the success of Broadchurch, but still slightly taken aback by the reaction.

“I suppose Broadchurch just took off, and I don’t think any of us expected that,” said the actor, who is filming the second series.

One of his biggest fans though is very close to home; his “brilliantly supportive” Scottish father: “He watches everything I’ve been in.”

Although Buchan’s mum died 14 years ago and didn’t live to see her son’s success, he’s pleased she did see him on stage while he was a student.

“My mum saw me play Hamlet,” he says. “She was very pleased about that, and had a tear in her eye afterwards.”