Harry, then 16, admitted last summer that he had drunk with friends at a pub near his father's Highgrove country estate and smoked marijuana with friends.

Rattlebone Inn: Scene of Harry's underage drinking

"The Queen shares the Prince of Wales' views on the seriousness of Prince Harry's behaviour and supports the action which has been taken," Buckingham Palace said in a statement.

"She hopes the matter can now be considered as closed."

Prime Minister Tony Blair - whose own son was found drunk in central London at age 16 - also praised Prince Charles' "sensitive" handling of the affair.

And Home Secretary David Blunkett agreed, adding that he welcomed the news media's attention to the problems of drug taking by young people.

But, as a father of three sons, he was "sorry" for the way Prince Harry had found himself under the spotlight in difficult circumstances, he said.

However police are refusing to rule out action against Prince Harry.

Focus on pub

Superintendent Mandy Evely, of Wiltshire Police, said the 17-year-old would be treated "exactly the same way" as any other young person.

"One of the newspapers has said it has a dossier of evidence against him," she told BBC News.

"We will be looking at that and if there is any evidence on which we can act then of course we will do that.

"We want to stop young people getting involved with drugs and alcohol."

Licensing laws

Illegal for under 18s to buy alcohol anywhere 16 and 17-year-olds can buy beer, porter, cider or perry with a meal not served in a bar Under 18s cannot drink in a bar but those aged five or more can elsewhere in licensed premises Source: DCMS

Prince Harry is reported to have drunk at the Rattlebone Inn, Wiltshire - which has since changed hands - and smoked a joint at one of the after-hours parties he held back at the estate.

Supt Evely said the licensees of the pub at the time would also be investigated.

A statement from Young's Brewery, based in Wandsworth, south London, which took over the Rattlebone Inn in March 2001, said it had carried out a "full inquiry" in view of the media attention on the pub.

"On a number of occasions since then, Prince Harry has visited the pub," the statement said.

"At no time was he served any alcoholic drink and he was always perfectly behaved."

Prince Harry resumed his studies at Eton on Monday, after spending Sunday at his Highgrove home.

He could face a urine check at the school with the risk of expulsion if he tests positive for drugs.

Any boy possessing, using or selling drugs at school during the term can expect to forfeit his place

Headmaster, John Lewis

The headmaster, John Lewis, said: "Where concerns exist about a boy's possible involvement in drugs, he will be counselled and warned, and urine tests are sometimes used to clarify the situation.

"Any boy possessing, using or selling drugs at school during the term can expect to forfeit his place."

But Mr Lewis added: "If there is drug use or suspicion of it in the holidays, we would expect parents to deal with it, as was done on this occasion."

The press watchdog said the story was "exceptional"

The Press Complaints Commission said that, despite the "exceptional" public interest in the current story, publications should not abandon their pledge to spare the young princes from media intrusion.

The director of the industry watchdog, Guy Black, said: "This was an exceptional matter of public interest.

"But this does not detract in any way from the tough rules that apply to all children, including Prince Harry, while they are at school."

BBC royal correspondent Jennie Bond said the prince's privacy at school is likely to be respected, as it has been in the past.

But she added: "Harry has put himself firmly in the spotlight, and he must now expect intense media scrutiny of his behaviour when he's out in public."

Harry, who is third in line to the throne, is said to be embarrassed and ashamed about the publicity.