Bono takes the stand to vouch for 'drunk' star Â

Unannounced and without fanfare, the rock star Bono made a fleeting appearance in court yesterday to defend his friend Peter Buck.

U2's lead singer told the jury at Isleworth Crown Court that he could not believe his "ears and eyes'' when he heard that the 45-year-old REM guitarist was accused of running amok through the first-class cabin of a transatlantic flight.

''I just wanted to stand up and be counted,'' he said, explaining why he had volunteered to be a character witness.

Just a few weeks after Time magazine put him on the front cover and asked if his debt relief campaign could save the world, Bono turned up alone at the west London court.

On a day dominated by evidence by medical experts, Mr Buck's barrister, Richard Ferguson QC, asked Judge Crocker if he could quickly allow one witness, Mr Paul Hewson.

Clad in a black suit and shirt and sporting a gold earring, the 41-year-old singer took the stand and greeted the judge with the words: "Hello there.''

''You are known as Bono, the lead singer of U2?'' asked Mr Ferguson. "For my sins," replied Bono, smiling.

But his manner became firmer when asked whether he had ever known Mr Buck – who has been accused of behaving like a "drunken lout'' on board a flight last year from Seattle to Heathrow – to drink excessively or take drugs.

''I have never, ever seen him drunk,'' replied the singer, adding: "I have absolutely never seen him take drugs.''

"I came over because he is actually famously known for being a peaceable person," Bono said.

"Of all the people in the music business I couldn't believe my ears and eyes. It did not add up to the person. I had to twist his arm to get him into a boxing match because he thought it was an aggressive sport. I just wanted to stand up and be counted. This is ridiculous. It is a very bizarre event and unusual."

Bono continued: "He is a famous parent. It is hard to get him to go on tour because he loves his kids [eight-year-old twin daughters] so much.

"He is a very quiet man. This may embarrass him but I had to come here and say it.''

He explained to the court that he had first met Mr Buck and fellow members of REM - whose hits include "Losing My Religion" and "Shiny Happy People" – during a concert 17 years ago at Milton Keynes.

Despite the fact the bands were based on opposite sides of the Atlantic – REM in Athens, Georgia, and U2 in Dublin – it had been the start of an enduring friendship.

Bono said: "They have played with us a good few times. Our groups' work has been in parallel for a number of years. They are one of the only groups that have had the same longevity as our group. There has been a certain amount of social interchange, we like each other's company.''

The court heard previously the pilot of the flight had considered diverting the British Airways 747 last April after Buck, who was said to have drunk 15 glasses of wine in three hours, allegedly assaulted staff, overturned a trolley, smashed crockery and tried to steal a knife.

Under cross-examination from David Bate QC, for the prosecution, Bono described Mr Buck as a moderate red wine drinker. The singer explained that he did not drink before a performance and would not expect any professional band member to do so either.

"Most people I know don't drink if they are seriously professional about what they do. But afterwards, yes, they would drink,'' he said.

After 10 minutes of evidence Bono bade the judge goodbye, before turning to wave at Mr Buck who nodded an acknowledgement from the dock.

The guitarist, who claims to have no memory of the flight after taking a sleeping pill with his wine, denies one charge of being drunk on the aircraft last April, two counts of common assault involving the cabin services director, Mario Agius, and a steward, Holly Ward, and one of criminal damage.

The jury was told that part of his defence relies on being mistaken for his tour manager, Robert Whittaker, and partly on a condition called non-insane automatism, brought on by a mix of medication and alcohol.

Professor Malcolm Lader OBE, an expert in psychiatry and clinical pharmacology, explained that 10 to 15mg of Zolpidem, with approximately eight units of alcohol could have resulted in a state similar to sleepwalking. Mr Buck would have appeared conscious but would not have been in control of his actions.

Cross-examined by Mr Bate, Professor Lader acknowledged that, in 30 years, he had only come across five similar cases.

The trial continues.