Douglas Adams’ Doctor Who script City of Death is to be turned into a novel by author James Goss.

Featuring Tom Baker as the fourth Doctor, City of Death –  a four-part serial – aired on BBC1 in 1979, watched by over 16 million viewers, and remains one of the most popular of the show’s story arcs. Alongside his companion Romana (Lalla Ward), it sees the Time Lord on holiday in Paris where villainous Count Scarlioni (Julian Glover) is scheming to invent time travel and reverse his ship’s explosion over primeval earth – a plot financed by forcing Leonardo da Vinci to paint multiple copies of the Mona Lisa to sell.

When the Doctor discovers the ship’s explosion was the spark for life on earth, he realises the Count must be stopped.

According to Adams’ biographer, Jem Roberts, the script had to be produced in a hurry when it became clear one Friday that the four-episode shoot set to begin on Monday had no storyline after it was left unfinished by David Fisher, one of the show’s writers, due to family problems.

In the words of The Hitchhiker’s Guide to the Galaxy author – then working as a script editor on Doctor Who – the show’s producer Graham Williams “took me back to his place, locked me in his study and hosed me down with whisky and black coffee for a few days.”

Now Goss is extending the late author’s storyline into a novel, due out in May. “It’s a book Douglas Adams was supposed to write,” he told The Guardian. “In the 80s, they wrote to him, and asked if he would like to write [his scripts] as novels – they even said they’d pay double. But he thanked them politely, and declined, and used his ideas in other books.”

Although, inevitably, Goss – who’s penned two Doctor Who novels and produced a radio adaptation of Shada, an unfinished Doctor Who story by Adams – is wary of the challenge of putting his own spin on the much-loved author’s work. “I knew people would be looking and saying: ‘Well, it’s not going to be as good as what he’d have written’… But in a way it was great, because I knew that every decision I’d make would be wrong.

“When you’re essentially ghost-writing, and for someone as good as Douglas Adams, you know readers will say: ‘That’s not how Adams would have done it.’ It took a lot of pressure off.”

James Goss’s novel based on City of Death is published on 21st May by BBC Books.