Andy Coulson, the former editor of the 'News of the World', has been detained by police investigating allegations of perjury.
Mr Coulson (44), who was British Prime Minister David Cameron's former director of communications, was detained by seven officers from Strathclyde Police at his home in the Dulwich area of London at 6.30am.
He was held for questioning over his evidence in the trial of Tommy Sheridan, the former leader of the Scottish Socialist Party, who was jailed in 2010 for lying under oath during a defamation case.
Mr Coulson was to be questioned in Glasgow by officers from the Operation Rubicon team, which was set up to look into allegations of phone hacking, breaches of data protection and perjury.
Mr Coulson, who was Mr Cameron's chief media adviser when he gave evidence, was called by Sheridan, who conducted his own defence.
In the earlier trial, Sheridan won £200,000 (€250,000) in damages after the newspaper disclosed he was a swinger and adulterer.
Mr Coulson told the trial that he had no knowledge of illegal activities by reporters while he was editor of the newspaper.
Sheridan claimed during the case that his mobile phone had been hacked by Glenn Mulcaire, the private detective who was jailed in 2007 along with Clive Goodman, the paper's royal editor, for intercepting voicemail messages.
Strathclyde Police said Mr Coulson had not been formally arrested at this stage. (© Daily Telegraph, London)