An Outlander insider last night said the meeting may have been why Sony "took the foot of the pedal" with finding a UK broadcaster.

The Sony email mentions the "importance" of the TV series to the political situation last year, and how it would likely be a "focus" of the meeting with Cameron.

Publication of the leaked email has further fuelled social media speculation that the UK Government did not want the show broadcast before the independence vote in September.

The speculation ran that the show's depiction of heroic, Gaelic-speaking Highlanders fighting red-jacketed British soldiers would lead to a boost of the Yes vote at the referendum.

Although a spokeswoman of the Prime Minister declined to comment last night, an Outlander insider, said that if Cameron had made an intervention on the transmission date of the show at the meeting, it would make sense.

The insider, with intimate knowledge of the show, said: "It makes complete sense as to why Sony took their foot off the pedal with UK sales.

"It was all systems go and they had the BBC up to see the set, etc, then there was a definite sense of trying to back pedal."

Outlander, based on the best selling books by Diana Gabaldon and shot in Scotland, was finally broadcast in the UK this year, well after other countries, some who saw the show last August.

It is now viewable on the Amazon Prime streaming system.

In the background briefing document for a "PM Cameron event" last summer, Mr Weaver writes to other Sony executives: "Your meeting with Prime Minister Cameron on Monday will likely focus on our overall investment in the U.K. - with special emphasis on the jobs created by Tommy Cooper [the ITV show], the importance of Outlander (i.e., particularly vis-a-vis the political issues in the U.K. as Scotland contemplates detachment this Fall), and the growth of our channels business..."

A spokeswoman for Sony declined to comment on the email.

A spokeswoman for the Prime Minister said last night said: "We do not comment on leaks."

She declined to comment on the meeting between Sony and the Prime Minister or whether he had asked for the transmission of the show to be delayed.

At last year's Edinburgh International Book Festival, Gabaldon speculated on why the UK broadcast of the series was apparently delayed and she mentioned the rumours linked to the independence referendum.

Gabaldon said: "There are in fact negotiating with one or more UK TV suppliers.

"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."

Pete Wishart, the SNP's candidate for Perth and North Perthshire, commented on the speculation that the Prime Minister intervened in discussions over the transmission of the programme.

He said: "If correct, this is a new low for David Cameron - who has been cutting the choice of television programmes people can watch for political reasons.

"A strong team of SNP MPs elected to Westminster on May 7 will make Scotland's voice heard like never before, end austerity and demand that no UK Prime Minister is able to censor like this."