Members of the public are regularly treated to the large green space behind the imposing Buckingham Palace, but they usually go free either as invited guests to garden parties or on special occasions like the Diamond Jubilee picnic earlier this year.

But next July, up to 60,000 visitors will be able to enter the gardens if they manage to buy tickets to a trade fair organised by the Royal Warrant Holders Association RWHA.L which decides which companies receive the coveted Royal Warrant.

The Coronation Festival will be held from July 11-14, and people wanting day tickets to visit trade stalls set up in the palace gardens will pay 30 pounds while those wanting to attend one of three evening galas will pay 90 pounds each.

There will be no concessions and tickets go on sale from December 16. The July 11 events are by invitation only.

"This will be the first time we've run an event of this kind in the gardens of Buckingham Palace," David Walker, Master of the Royal Household, told reporters at a briefing held at the palace on Tuesday.

Asked whether the royal family should be charging people to use the garden, he added: "This has got to stand on its own two feet commercially and is a very expensive event to stage."

Companies with the royal seal of approval must pay to have a stall at the fair, and RWHA secretary Richard Peck said the event was designed to celebrate innovation and excellence in British industry and to boost exports and investment.

"We want to dispel this myth that craft has no relevance in modern industry," he said. "In fact, it underpins modern industry."

Walker said he could not say which royals would attend the concerts, but that there was a "reasonable expectation" that members of the family would be present.

Asked which performers would take the stage, he replied: "There will be some very big names."

He added that the ticket prices were in line with comparable events, and that any profit would be shared between the royal household, the RWHA and Media 10, the private events company helping to stage the fair.

The royal family would invest its profits in up to 10 apprenticeships in British industry.

The Coronation Festival is one of several events likely to be staged for the 60th anniversary of Queen Elizabeth's coronation in Westminster Abbey.

But they are unlikely to match the scale of this year's nationwide Diamond Jubilee celebrations marking her accession to the throne on the death of her father King George VI which were attended by millions of people. (Reporting by Mike Collett-White, editing by Paul Casciato)

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