David Nicholls regrets cutting one thing from his BBC adaptation of Us

The book follows a married couple, Douglas (Tom Hollander) and Connie (Saskia Reeves), who embark on a once-in-a-lifetime tour of Europe with their teenage son - despite Connie's assertions that she no longer wants to be married to Douglas.

Speaking during a press Q&A alongside various cast members, Nicholls revealed that a number of locations featured in the novel had to be cut - including Munich in Germany, where tensions boil over in the book.

Asked about the challenges of adapting the novel for screen, he said, "When you put that [extensive travelling] in the script, it becomes a series of negotiations, because it's hugely problematic, and you can't... there's an episode in the book where he has an hour to see Florence and he tries and it goes wrong, and it's a really lovely little set piece but you can't just drop that in, you have to make certain allowances, so we did have to cross out Munich, and Madrid, and one or two museums."

He continued, "There's the pragmatic business of filming the story and the changes you have to make to make that work. I'm still sad we didn't quite get to Munich, there's some good stuff in Munich. The break-up and... there's a long, simmering, dark night on a sleeper train from Amsterdam to Munich, and then it all explodes in Munich... [But] it's the business of adaptation."

However, the four-part adaptation still manages to pack in a number of European cities and famous museums, including the Louvre in Paris, which features heavily in episode one.

Us starts on BBC One this Sunday (20th September) at 9pm with all four episodes being available on BBC iPlayer after it’s aired. Check out what else is on with our TV Guide.