Cleared, the oil billionaire 'too absent-minded' to spy on his Jimmy Choo tycoon ex

Oil and banking heir Matthew Mellon was yesterday cleared of hacking into his ex-wife's emails - after the court was effectively told he was incapable of the crime.

The 43-year-old faced up to five years in jail if found guilty of spying on Tamara Mellon, the Jimmy Choo fashion tycoon.

But throughout the trial, witnesses described him as an absent-minded incompetent - who had no idea the detectives he hired were breaking the law.

Mr Mellon bowed his head after being acquitted and said outside court: "I am obviously thrilled with the verdict, particularly because it is the right verdict.

"It has been a difficult experience and I am pleased it is over."

He had been accused of hiring private eyes to spy on Mrs Mellon's emails to obtain details of her finances during their acrimonious divorce wrangles.

Although she appeared for the prosecution, his ex-wife spent 90 minutes in the witness box portraying the former cocaine addict and playboy as a loving but bumbling incompetent.

She described Mr Mellon, the heir to a £4 billion U.S. dynasty, as a "child in need of a nanny" who was so absent-minded he would "miss planes like other people missed buses".

He couldn't manage bills and bank accounts, she said, adding: "Matthew can't even read a comic book, let alone a legal document."

Defence QC Nicholas Purnell insisted that even without Mr Mellon's poor attention span - which a prosecution psychologist consigned to the bottom 11 per cent of the population - there was no way he could have known City based Active Investigation Services would break the law.

He said Mr Mellon paid the firm £12,000 to check whether his 38-year-old ex-wife was concealing financial information - only to be "duped and gulled".

The jury at Southwark Crown Court cleared Mr Mellon, of Belgravia, Central London, of unlawfully conspiring to cause unauthorised modification of computer material during 2004 and 2005, after five days of deliberations.

Two of his co-defendants in the case were convicted and will be sentenced later.

After the verdict, Mrs Mellon's solicitor Elizabeth Robertson said: "Matthew Mellon remains a good friend and is, of course, the father to Tamara's daughter. Tamara is therefore delighted by the jury's verdict today."

The high-profile couple met in 1997 at Narcotics Anonymous. Their close friends Elizabeth Hurley and Hugh Grant were among the guests at their glitzy society wedding at Blenheim Palace two years later.

But in 2003, soon after the birth of their daughter Minty, the relationship foundered.

Mrs Mellon this year sold her global fashion firm for £185 million, but remains its president.

She told the court that after her lawyers refused requests to disclose the value of her company, she began to receive suspicious emails.

Mr Mellon had hired AIS, but only much later learned that the firm had contacted American computer hacker Marc Carron for one of his illegal viruses.

Carron sent three emails to Mrs Mellon's London headquarters apparently offering her sympathy and help in her divorce battle.

He wanted to tempt her into opening the emails, which would have installed a bug allowing him to access all her confidential files.

But the plan backfired when Mrs Mellon became suspicious of their "sleazy" nature and passed them to her IT chief.

When police arrested Mr Mellon in February 2005, he said he had been told that AIS methods were legal because the agency was run by former police officers.

He was one of a string of AIS customers using the agency's illicit "Hackers are Us" sideline.

Some, like him, were in the throes of divorce while others were involved in sensitive business disagreements.

The agency's charges ranged from £3,000 for bugging a phone to £5,000 to hack into a computer.

Yesterday, ex-policeman Scott Gelsthorpe, 32, from Kettering, Northamptonshire, who helped run the agency, was found guilty of two conspiracy counts and one of conspiring to unlawfully intercept computer material.

David Carroll, 58, of Highgate, North London, was found guilty of six conspiracy charges.

Carroll's computer expert son Daniel, 36, from Westminster, was cleared of two charges and Maurice Kennedy, 58, of Barnet, North London, who asked AIS to help him during his looming divorce, was acquitted of an interception conspiracy.

AIS chief Jeremy Young, 38, from Ilford, Essex, another former Metropolitan Police officer who used long-term sick leave to run the agency admitted 15 conspiracy charges before the trial and will be sentenced with Gelsthorpe and Carroll.