Downton Abbey creator Julian Fellowes has admitted he does “not fully understand” why the show has become such a hit with viewers.

Speaking on Radio 4’s Desert Island Discs, he admitted that he remained baffled about the success of the period drama, which recently completed its second series on ITV1 – and added that if he knew what had made it so popular he would be able to repeat the formula.

“If I had a clear understanding of why it had done so well I would continue to write shows that attracted record viewers for the rest of my life,” Fellowes said.

“I don’t fully understand why it did so well.”

“I think we did one or two things right but for me I think the main reason it was so popular was we are allowed to give completely equal weight to all of our characters and we don’t set them off in a group, so we don’t make all the toffs horrible or all the servants funny.”

Fellowes – who chose songs by soul singers Marvin Gaye and Macy Gray on the show – also confessed that he had been “a bit pompous” about complaints viewers made about the historical accuracy of the show and its use of modern phrases.

“Papers are not full of complaints about a programme that no one’s watching. I think I misinterpreted what was an expression of the joint experience,” he pointed out.