THE Tommy Sheridan trial was a factor in Andy Coulson's decision to quit as the Prime Minister's chief spin doctor, after months of speculation over his role in the News of the World phone tapping scandal, senior Downing Street figures have revealed.
• Andy Coulson said he had become the story Picture: Getty Images
His resignation is a major blow to David Cameron, and opponents have questioned his judgment in employing and standing by a man whose past was under such close scrutiny.
There were concerns among senior Tories last night that Mr Cameron would struggle to find somebody to replace Mr Coulson with someone who had the "same connection to the real world" outside the "old Etonian elite" in Downing Street.
In a statement, Mr Coulson said he had become the story and was unable to give the "110 per cent required" to be director of communications at Downing Street.
He had come under increasing pressure over the practices at the News of the World of phone tapping politicians, sports stars and celebrities under his editorship.
While denying any knowledge of phone tapping and claiming the paper's former royal correspondent Clive Goodman, who went to prison, had been "a rogue reporter", he said that dealing with the allegations was becoming too much of a distraction.
"I stand by what I've said about those events but when the spokesman needs a spokesman it's time to move on," he said.
One of those distractions, which is said by insiders to have finally helped make up his mind, was his appearance at Sheridan's perjury trial in Glasgow last month.
The charges related to statements Sheridan made in court when he successfully sued the News of the World about stories regarding his involvement with swingers clubs.
A Downing Street insider told The Scotsman: "While the Tommy Sheridan trial is not the reason he resigned, it is fair to say that it certainly didn't help.
"It was one of the many things getting in his way and taking up his time that meant he couldn't do his job properly.
"He had to spend two or three days preparing for the trial and these things build up."
Sheridan is appealing against his conviction for perjury and yesterday his lawyer, Aamer Anwar, said: "At the trial of Tommy Sheridan, Andy Coulson gave evidence under oath that he had no knowledge of phone hacking, despite Glen Mulcaire (a private investigator who did work for the News of the World and was sent to prison for phone hacking] having Mr Sheridan's mobile phone number and personal details. His evidence should now be re-examined by the authorities."
Mr Coulson's resignation deflect attention from the sudden decision by shadow chancellor Alan Johnson to quit on Thursday over stories about an affair between his wife and a policeman who protected them while he was home secretary.
And Labour leader Ed Miliband, who was visiting Scotland, went on the attack, questioning Mr Cameron's judgment. He said: "Personally, I think Mr Coulson should have gone earlier. I think David Cameron made the wrong judgment in keeping him, when clearly they were going to make his job, at the very least, more difficult."
As news of a personal statement from Mr Coulson began to circulate yesterday morning, Downing Street put out an initial statement saying the Prime Minister had full confidence in his most senior adviser - Mr Cameron has regularly admitted it caused him sleepless nights if he went against his judgment. Once the resignation was announced, Mr Cameron defended Mr Coulson and said it was wrong for him to be punished twice, having already quit as News of the World editor four years ago over the same allegations.
"He's run the Downing Street press office in a professional, competent and good way," the Prime Minister insisted. "He's done an excellent, excellent job. I think he should be judged by that. This is all about the past. It's just gone on and on."
However, with the Crown Prosecution Service reviewing the evidence on the phone-tapping allegations, Labour MPs who believe they were victims of the Coulson regime at the tabloid were pushing for further inquiries.
Labour MP Tom Watson said: "This is the second job that Andy Coulson has resigned from for something he claims to know nothing about."
He also noted that the announcement had come just as Tony Blair was giving evidence to the Chilcot inquiry.
He said: "It's a mark of the man that he would sneak out a statement on a Friday morning on a busy news day.
"Spin and obfuscation is all we get from Downing Street - we need to get to the truth."
Profile: Essex-boy showbiz reporter who rose to the top in Fleet Street, then Downing Street
Andy Coulson was the tabloid journalist who brought to David Cameron's team a killer instinct for what made news.
Three and half years after he was appointed the Tories' chief spin doctor, however, he knew he was becoming the news himself.
Mr Coulson, 43, sought to avoid comparisons with Alastair Campbell - another former tabloid hack - by taking a much lower profile in Westminster as the Tory leader's head of communications. But he could never shake off the explosive allegations against him from his time as editor of the News of the World. He denies any knowledge of phone hacking by reporters under his editorship, but the story has only intensified since he entered Downing Street.
An Essex boy done good, Mr Coulson brought a unique perspective to the most senior levels of the Conservative Party. The team is dominated by public school and Oxbridge graduates, but Mr Coulson attended a state comprehensive and worked for a local paper instead of going to university.
He did not even have a background in political journalism, instead following the showbiz route to the top of the News of the World via the Sun. But his tabloid career was left in tatters after his royal editor Clive Goodman was jailed for illegally intercepting phone messages from Clarence House. Mr Coulson said he had "ultimate responsibility" for the scandal and apologised "unreservedly" to princes William and Harry.
Yet only months later, in May 2007, he was unveiled as director of communications and planning with the Tories.