Royal protection officers - walking a thin line

He said there were "many occasions" when he had been forced to overlook a client's "misdemeanours".

He added; "I once looked after a band - not a huge group, but certainly well-known - and there was a lot of drug-taking.

"We have a code we follow which says anything the client does is confidential but of course some may say we have a duty to report it when people flout the law.

"I never do - or I would never work again. No-one would trust me.

'Butlers with guns'

"I think the guys did the right thing here. If they did know - it is none of their business and if, as they say, they didn't, then they were obviously concentrating on security and leaving the prince's private life alone.

"That's their job after all."

SO14 - the role

the personal protection of members of The Royal Family in the UK and abroad the physical protection of the Royal Palaces and Residences the technical protection of all Royal Residences and Estates the personal protection of certain members of foreign royal families visiting the UK provision of escorts for Royalty, visiting Heads of States, other VIPs, high risk prisoners and valuable loads

The royal family's security - which usually costs around �30m a year - is looked after by SO14, the Metropolitan Police's Protection Squad, sometimes described by their Special Branch rivals as "butlers with guns".

They are a crack team of police officers charged with protecting the monarchy.

Known as the Royalty and Diplomatic Protection Department, members are responsible for personal safety and guarding royal residences.

It is unclear whether Harry's bodyguards were with him as he drank and smoked.

But in any case, said royal author Penny Junor, they only have the authority to stop the boys from doing something when it directly affected their safety.

"They are there to protect the princes from danger or assassination....not from the normal kind of episodes in growing up," she added.

Moral judgements

Prince Harry's bodyguard at the time is reportedly keeping his job since his role is about safety, not making moral judgements - a view echoed by Jennie Bond.

"They are with them constantly and do not want the royals to think Mr Plod is breathing down their necks all the time."

Scotland Yard refused to comment in detail, saying they did not discuss security issues

"We do not discuss matters of security.

"But - in relation to the weekend's revelations - our protection officers have not made any reports of security concerns, and security has not been compromised."