THE writer of the best-selling Outlander books, Diana Gabaldon, has rejected rumours that the TV adaptation is being held back from a UK broadcast by the independence referendum.

At an appearance at the Edinburgh International Book Festival, Gabaldon said she does not know why the successful US version of her Scottish-themed romantic time travel books are not yet being shown in the UK, where they were filmed.

The first episode was shown on August 9 in the US and had five million viewers, and the second episode added 25 per cent more audience, the author said.

However, she added that Sony was still in negotiations about a UK broadcast. "There are in fact negotiating with one or more UK TV suppliers," she added. "Why that deal has not come to a conclusion, I don't know, they have been at it for three months at least.

"There has been talk and rumour and speculation, even though there is no evidence on which to speculate, but the most common rumour is they are waiting until after the Scottish referendum - but there is no evidence to suggest that is true. You can take that for what it's worth."

She said the first two books would likely be a series in itself as the third book in the series is larger and more complex.

The author also said she would like to see her Lord John Grey books become its own TV series.

Ms Gabaldon said that Sam Heughan was perfect for the role of Jamie Fraser.

She said there had been talk of the actor Chris Hemsworth, who stars as Thor in the successful superhero movies about the character, taking the role. But she said: "Putting aside his nose, which is not Jamie Fraser at all, no-one would ever be able to look at him without seeing Thor. And beside he is Australian, he would not be able to do a Scottish accent.

"I wanted a Scottish actor if humanly possible and Sam is from Dumfries and Galloway."

She confirmed that the Scottish actor Frazer Hines, who she first saw in a kilt in an episode of Doctor Who as the character Jamie McCrimmon, which partly inspired Outlander, will appear in the new series as a prison governor. "He is a lovely guy and I am really pleased," she said, "He will be Sir Fletcher Gordon, the governor of Wentworth Prison."

In a lively question-and-answer session, Ms Gabaldon also said the first image she had for the nine-book series was a man in a kilt.

She said: "I was once asked by a German interviewer: 'Can you tell me, what do you see when you see a man in a kilt?'

"I was really tired and I said, 'I suppose it's the idea that you could be up against a wall with him in a minute'."

The last answer reduced the packed main theatre of the ­festival to gales of laughter.

Ms Gabaldon was in ­Cumbernauld yesterday at a script reading for the show.