SNP deputy leader Nicola Sturgeon has criticised the Tories after more secret footage of former co-treasurer Peter Cruddas was released

A senior Conservative has been filmed describing how the party must fight to keep the UK together "even if they don't agree with it" in order to tell Scots what powers they will be denied in post-independence negotiations, it has been reported.

More footage is set to be released of former Tory co-treasurer Peter Cruddas talking to an undercover Sunday Times reporter.

Mr Cruddas quit last weekend after the newspaper published secret recordings in which he urged undercover reporters to give more than £250,000 in return for direct face-time with senior ministers.

The report sparked calls for an independent inquiry into allegations that Mr Cruddas was negotiating "cash for access". Further excerpts of the conversation have been released to broadcasters this evening, with more footage to follow on the Sunday Times website.

According to reports on the BBC and STV news websites, Mr Cruddas said Prime Minister David Cameron "wants to fight to keep the Union". Mr Cruddas added: "He told me that was, those were his true feelings, however, even if they're not, we as a party have to be seen to be fighting to keep the Union together.

"Even if we don't agree with it, because at the end of it all, if the Scots say we're out of here and they want to go independent, we can turn around and say it's not what we wanted, it's not what we campaigned for, you can't have this, you can't have that, and you can get on with it."

Last week, the newspaper also said Mr Cruddas claimed he and Mr Cameron jokingly refer to Scottish First Minister Alex Salmond as "the mad Scotsman", although a party spokesman denied Mr Cameron had ever used the phrase.

Commenting on the latest footage, Deputy Scottish First Minister Nicola Sturgeon said: "This is another bombshell for the Scottish Tories who are isolated and irrelevant in the games being played by their London bosses. It shows that senior Tories in London are cynically faking their opposition to independence to position themselves for a post independence deal.

"The Cruddas revelations show that they believe in nothing except protecting Westminster interests. Their claims about winning the referendum are exposed as mere bravado. In fact they are already preparing for losing.

"After a rich man's Budget, a petrol panic and now the exposure of their true feelings towards Scotland the last Tory would be as well turning in their membership card now."

PA