TOMMY Sheridan has said the arrest of David Cameron's ex-communications chief Andy Coulson on suspicion of committing perjury is the first stage towards him clearing his name.

He said it proved News International was a "rotten orchard" full of "industrial scale criminality."

The former Scottish Socialist Party leader was recently released from a three year prison term after being convicted of lying at his defamation trial against the News of the World, which Coulson once edited.

Coulson, who resigned from the paper after his royal editor and a private investigator were jailed for intercepting voicemail messages, testified at Mr Sheridan's perjury trial in 2010.

After it emerged Coulson had been taken from his London home yesterday to Govan police station, Mr Sheridan said: "We were led to believe by Mr Coulson and his acolytes at News International during my trial and the initial phone-hacking investigations that the problem was a rogue reporter.

"I think we all know now that there is no bad apple in the barrel. What there is is a rotten orchard full of bad apples."

He said the work of Strathclyde Police's Operation Rubicon, which is examining whether witnesses lied to the court during Mr Sheridan's trial as part of its investigation into phone hacking, helped his hopes of overturning his conviction.

Speaking outside his home, Mr Sheridan added: "We now have a start to what will hopefully become criminal charges and hopefully Mr Coulson won't be lonely but he will be joined by colleagues in the future.

"I believe today marks the first step in the journey towards the quashing of my conviction, which was unsafe and unsound."

The former MSP is considering an appeal following his release from prison in January, where he served one-third of his three-year sentence for perjury.

His solicitor Gordon Dangerfield said: "We have very strong grounds of appeal and will be lodging a full appeal in due course.

"Today's developments concern only one of various areas which are relevant to the appeal, and which are being actively pursued by us.

"We are very limited in what we can say because much of the information which we have is still confidential at this stage and we do not want to prejudice the ongoing investigation.

"We are very much looking forward to being able to present all of the new evidence at a full appeal in due course.

"We believe when the whole truth comes out, the public will be given an entirely new perspective on what the Tommy Sheridan trial was really about.

"It is safe to say that many people will have their eyes opened for the first time."

Lawyer Aamer Anwar, who represented the former MSP during the trial, had previously said Coulson was not above the law. Yesterday, Mr Anwar, who now writes a weekly column for a News International newspaper, was more circumspect.

He said: "Everyone is entitled to the presumption of innocence and it would be inappropriate to comment on Mr Coulson's detention today."

Calling for an urgent review, Labour MP and phone hacking campaigner Tom Watson called for First Minister Alex Salmond to launch an immediate inquiry into illicit "information techniques" used by News International employees in Scotland.

The First Minister has ruled out an inquiry and refused to disclose whether he had been a victim of hacking.

Mr Watson said: "It is now abundantly clear that members of the jury were not in full possession of the facts. If the First Minister had any honour, he would launch an inquiry."