For an entrance fee of £8 - with reductions for children and the elderly - tourists would be able to see the State Apartments and a priceless collection of paintings, furniture and porcelain.
The aim was to raise money to pay for repairing Windsor Castle, which had been ravaged by fire in November 1992.
It was announced that the palace would be open to the public each August and September for five years, after which the scheme would be reviewed. But visitors were unlikely to catch a glimpse of any senior royals, as most of the family would be at Balmoral.
Opening up the palace was the Queen's own idea, finalised after consultation with Premier John Major and announced in the Commons by Heritage Secretary Peter Brooke.
The Government reckoned that 70 per cent of the £40 million cost of rebuilding Windsor Castle would be raised by the Queen's decision, coupled with the proceeds of the £3 a head charge to be imposed for entrance to the castle precincts, which had previously been free.
At the time of the announcement the exact route of the visitor tour had yet to be determined, but visitors were expected to be allowed to see the main apartments, including the throne room, the state dining room and the 155 ft (47m) long picture gallery.
They would also be able to look into the famous balcony on which newly-wed royals traditionally kiss.
The royal household hoped that about 400,000 visitors will come to Buckingham Palace, much of it designed by John Nash for George IV, during the eight weeks that it was to be open.
Within a week of tickets going on sale, all advance group booking slots to visit Buckingham Palace had been filled for the next three years.
In the run up to its first summer season, fine art conservators, cleaners, painters, carpenters and officials were all hard at work to get the State Rooms ready for the moment when the palace greeted its paying public.
People who had queued for hours, even days, to pay their £8 entry fee said every minute of the wait had been worth it once they stepped inside.
Among those first through the doors was Merv Dunn, aged 60, a retired builder from TaPeka Point, New Zealand, who dressed for the occasion in a top hat and tails.
He was delighted with his tour of the royal palace, saying: "My eyes were boggling. It was incredible, it was wonderful, absolutely spectacular splendour and regal flamboyancy."
Alongside Mr Dunn in the queue, were Richard Simpson and Pamala Ellis, both 22. Richard said: "It is absolutely magnificent. We enjoyed it very, very much. It is definitely good value for money. I think it will be packed every day for the next two months.''
But 23-year-old South African Keri Humphrey was not so impressed, as she had hoped to see fewer ornaments and paintings and more sign of the daily life of the Royal Family.
After standing in the queue all night with her boyfriend, Greg Wertheim, she said: "It was a bit disappointing. I wanted to see more things like the bedrooms. It is beautiful but it is just pictures and furniture, pictures and furniture."
About 380,000 people visited the palace in the first year. This figure rose above 400,000 for the next two years but then levelled off to about 300,000 a year ever since.
Despite the original decision to accept visitors only until 1997, the Palace has continued to open its doors even after the restoration of Windsor Castle was complete, and remains one of London's top tourist attractions.
A new company, the Royal Collection Trust, was set up to manage visitors to Buckingham Palace, Windsor Castle and Holyrood House in Edinburgh.
Since then the trust has opened the Buckingham Palace ballroom as well as part of the gardens. It has also put £20 million into the development of the Queen's Gallery, which opened in 2001.
In August 2003, Prince Charles also allowed tourists to see his new London residence, Clarence House, the former home of the Queen Mother.
The palace tour has included a number of different exhibitions over the years including a display to celebrate Her Majesty's 80th birthday and the 60th anniversary of the Queen's marriage to the Duke of Edinburgh.