Paul Burrell's successful legal action against Mirror Group Newspapers (MGN) is the latest in a series of similar claims brought by public figures and celebrities against British tabloids.

Burrell took MGN to court after being targeted by private investigators instructed by the publisher and had his voicemails intercepted.

"I am pleased to announce that the defendant has now accepted responsibility for its unlawful actions, admitted liability and has agreed to apologise to the claimant for the repeated invasion of his privacy," said Burrell's lawyer Francis Leonard.

Leonard said that MGN had targeted Burrell's voicemail messages and also instructed private investigators at least three times between 2001 and 2002.

This led to the publication of "numerous articles concerning the claimant arising from unlawfully obtained information which severely impacted his reputation", he added.

"Between 1995 and 2008 the claimant was targeted by the defendant because he was a close friend and trusted confidante to Princess Diana and then subsequently because of his role within the public sphere following his departure from the royal household," Leonard said.

"During Diana's lifetime, the activities of the defendant caused his relationship with her to deteriorate as she wrongly thought that her highly sensitive personal information was being leaked to the press."

'Great psychological harm'

MGN -- which publishes the Daily Mirror, Sunday Mirror and The People -- had agreed to pay substantial damages plus his legal costs and accept liability for the unlawful acts, Leonard said.

The use of the unlawfully obtained information in the press undermined Burrell's relationship with his legal team as he prepared for his criminal trial over accusations that he stole hundreds of items from Diana's estate.

Burrell was cleared of the charges in 2002 after it emerged that he had informed Queen Elizabeth II shortly after the princess's death in August 1997 that he had taken some items for safekeeping.

"In relation to his criminal trial, the intense negative daily press coverage led to a disintegration of the claimant's relationship with his wife and children, causing great psychological harm," Leonard said.

Alexander Vakil, for MGN, apologised on behalf of his client.

"The defendant is here today through me to offer its sincere apologies to the claimant for the damage, as well as the distress caused to him by the obtaining of his private information and the accessing of his voicemail messages," he said.

"It has undertaken never to repeat these actions.

"The defendant acknowledges this information should never have been obtained or used in the manner it was and that it is liable for the misuse of private information."