PRINCESS Anne coolly stared down the barrel of the deranged gunman's revolver and in her crystal-cut accent told him his attempt to kidnap her was not "bloody likely".

As she argued with Ian Ball, a 26-year-old petty thief described as a "nutcase", she was in fact on the point of delivering a royal biff to his nose when discretion got the better part of valour. The princess later admitted in a private note: "I nearly lost my temper with him but I knew that if I did, I should hit him and he would shoot me."

Ball's crackpot plan involved ransoming the princess for Pounds2m. During a six-minute incident, he wounded four men and was later sentenced to life imprisonment and placed in a psychiatric hospital.

Details of the failed kidnap attempt on the-then 23-yearold royal are published today by the National Archives under the 30-year rule for releasing confidential Whitehall documents.

They reveal not only the high drama that took place on The Mall one blustery night in March 1974, but also the sangfroid displayed by Princess Anne and the bravery of her protection officers.

The incident - the closest any member of the royal family has been to being abducted - occurred as the princess and Captain Mark Phillips, her husband of five months, were being driven back to Buckingham Palace following a charity film show.

They were only yards from the palace lights when, suddenly, Ball's Ford Escort swung in front of the royal limousine, causing it to stop. The royal couple were instantly thrown to the floor of the Rolls-Royce.

Confidential papers describe how the gunman rushed to the side of the royal car, pointed his revolver at the princess and said: "I want you to come with me for a day or two because I want Pounds2m. Will you get out of the car?"

To which, HRH replied sarcastically: "Bloody likely; and I haven't got Pounds2m."

In one document, Robert Armstrong, private secretary to Harold Wilson, the-then prime minister, recounted the princess's thoughts at the time.

"It was all so infuriating. I kept saying I didn't want to get out of the car and I was not going to get out of the car."

Showing presence of mind, Princess Anne then made a dive to get out of her vehicle from the opposite side to where Ball was standing, causing him to go round the limousine and into the path of her protection officers.

The confidential memo read:

"Sure enough, Ball fell for it.

He dashed round to the other side and was apprehended."

Moments earlier, Inspector James Beaton, the royal bodyguard, fired one shot before his weapon jammed. He threw himself into the back seat to shield the couple and was shot twice. Ball tried to pull the princess out but Captain Phillips managed to keep the door shut.

PC Michael Hills, a second officer on the scene, was shot and Reg Callender, the royal chauffeur, was wounded. Brian McConnell, a freelance journalist who had been in a taxi behind the princess's car, intervened, telling Ball: "Don't be silly, old boy, put the gun down." But he too was shot.

The gunman was finally subdued by another police officer who brought him down with a flying tackle as he tried to get away.

In court, Ball pleaded guilty to charges of attempted murder and attempted kidnap, and was imprisoned indefinitely under the Mental Health Act.

Officials, who launched a major reassessment over how the royal family should be protected, believed Ball had no political motive. Mr Armstrong noted howBall had worked out his plan "with care and

attention to detail" but concluded it was the work "of an isolated nutcase".

The police officers were awarded medals, with Inspector Beaton receiving the George Cross for his selfless act of bravery.

Princess Anne's composure clearly impressed Mr Wilson, who wrote in

green ink at the top of the file: "A very good story. Pity the Palace can't let it come out. Perhaps it will in court. HW."

A fortnight later in government correspondence, the PM was able to officially praise the princess for having behaved with "quite extraordinary courage and presence of mind".