The newspaper publisher Trinity Mirror has included the Countess of Wessex's former business partner in its internal investigation into allegations of phone hacking at the company's national titles.
Murray Harkin, a businessman who co-founded the public relations consultancy RJH in 1997 with the then Sophie Rhys-Jones, is reported to be considering legal action against the Sunday Mirror over an article it published in 2001.
His case is believed to centre on claims that he was followed while on a foreign holiday, and that his whereabouts could have been discovered only by someone who had access to his mobile phone voicemails.
Trinity Mirror's chief executive, Simon Fox, told staff by email today that although it had not yet been contacted by Mr Harkin or his legal representatives, he had asked his inquiry team, which was already investigating four civil actions against Mirror titles, to add Mr Harkin to the investigation.
In 2001, the Countess was the subject of a sting operation by the News of the World's "fake sheikh". She later stood aside as chairman of RJH after incurring heavy legal costs, and the loss of a prestigious client. A confidential separation agreement with Mr Harkin, then RJH's managing director, was put in place. The firm collapsed in 2006 and claimed it had never recovered from the NOTW sting.
Mr Fox's email, confirmed by a spokesman for the company, said: "I am absolutely clear that if any wrongdoing happened within the company, then we have no alternative other than to fully investigate and surface it." He added: "We have no reason to believe there is any substance to this accusation."