The Inspectorate of Constabulary (HMIC) says police officers who guard royalty must be given psychiatric training to help them deal with such situations.

Home Affairs Correspondent Jane Peel: Police say psychiatric training needed

The warning follows a series of incidents at Royal palaces, the most famous of which was in 1982 when Michael Fagan broke into the Queen's bedroom at Buckingham Palace in central London.

In 1997, the late Princess of Wales was said to be "distraught" after a mystery intruder to Kensington Palace forced a lock at the Orangery, adjacent to her living quarters.

In the same year, an escaped psychiatric patient evaded security to get into the grounds of Buckingham Palace while the Queen was away.

The squad was set up after Michael Fagan climbed into the Queen's bedroom

Other Palace intruders in recent years have included a group of lesbian anti-nuclear demonstrators who scaled the walls with ladders, and an American paraglider who landed on the roof as a stunt.

In a report on the Royal Protection Squad published on Wednesday, the HMIC's Colin Smith said the unit had been "very successful", with no "disabling attacks" on any royal figure and very few incursions into palaces.

But he said police were aware of about 60 people, about half of whom came to notice by visiting Buckingham Palace, who could pose a potential threat.

'Most are harmless'

Mr Smith says there has never been any training for protection officers in how to deal with individuals who appear to have a fixation with royalty.

A man protests at Buckingham Palace at his right to appear naked in public

Most of the 6,000 are harmless, said Mr Smith, but officers must make split-second judgements on how to react.

The call for better training for officers was echoed by mental health charities.

Paul Corry of the National Schizophrenic Fellowship, which runs training courses for several police forces, said it was vital Royal Protection officers were well-trained.

He said they must be able to assess immediately who is simply in mental distress, and who is a criminal intent on damage.

Officers need to know how to handle a confrontation without inflaming a "crisis" situation, he said - especially as they are routinely armed.

Delusions of grandeur

The reason for royal family members attracted such attention partly because of their fame, and partly because of their perceived position as the ultimate state authority.

Diana: "Distraught" after a mystery intrusion into her home

Mr Corry said: "If you've had your benefits stopped or you're feeling persecuted by your local services you tend to appeal to the highest authority in the land."

He said one schizophrenic disorder was delusion of grandeur.

Mr Corry said: "People may stroll into Buckingham Palace believing that they are the Queen or King of England.

"The royal family are public figures and they are in most people's consciousness. The fame of the royal family is immense.

"If doctors are testing somebody who is concussed, they will ask: 'Who is the Queen of England?' rather than 'Who is the Prime Minister?' or 'Who is number one in the pop charts?' - because everyone knows it."