The Queen acknowledges the Prince of Wales's choice in women, at last: 2003

Three decades after Camilla Parker Bowles first met the Prince of Wales, the Queen is to acknowledge their relationship publicly for the first time. She has invited Parker Bowles to next month’s jubilee classical concert in the grounds of Buckingham Palace. The couple will sit together in the royal box not far from the monarch.

The invitation is an unprecedented gesture of friendship by the Queen towards Prince Charles’s companion, with whom relations have previously been frosty. Charles is said to be “pleased and surprised” by the move. It is also a sign of how the deaths of Princess Margaret and the Queen Mother have brought Charles and the Queen closer.

Parker Bowles’s speech in Lisbon yesterday at a conference on osteoporosis showed her independent role growing in parallel with the openness of her relationship with Charles.

The couple’s appearance will be at one of the highlights of the golden jubilee in front of a live audience of 12,000 and millions watching on television. The invitation was instigated by the Queen and her advisers and organised by Sir Michael Peat, keeper of the privy purse and due to be Charles’s private secretary after the jubilee.

It allows Charles and Camilla, whose relationship the prince calls “non-negotiable” to appear for the first time together at an important royal occasion. Their public profile has been carefully choreographed by the prince's advisers at St James's Palace and by Buckingham Palace.

At the concert on June 1, called the Prom at the Palace, most of the guests will be members of the public who applied for tickets and have been chosen by ballot. They will be treated to a picnic in the palace gardens, including half a bottle of champagne, and will then hear a performance by the BBC Symphony Orchestra conducted by Sir Andrew Davis. The concert will feature Dame Kiri Te Kanawa and Sir Thomas Allen, the opera singers, and Mstislav Rostropovich, the Russian cellist.

In March Rostropovich also appeared at a concert to celebrate his 75th birthday organised by Charles at Buckingham Palace with Parker Bowles present. The evening, in the presence of members of the royal family and assorted European royalty, was the first official occasion attended by the Queen at the palace with both Charles and Camilla present.

Courtiers went to great lengths to ensure that the Queen and Parker Bowles were not pictured together. This will be more difficult to achieve in such a public setting as next month's concert. The appearance will be reminiscent of the couple's "coming out" at the Ritz hotel in London in 1999.

 They were photographed walking down the hotel steps together after the 50th birthday party of Parker Bowles's sister Annabel. Photographers had been tipped off days in advance about the appearance. Parker Bowles's growing status was evident as Luc Delafosse, the hotel manager, bowed low to her.

The occasion was the first public evidence of a relationship that for decades was on and off and was conducted surreptitiously.The prince and Camilla first met in the early 1970s and had a brief liaison. In 1973 Camilla married Andrew Parker Bowles, a godson of the Queen Mother. He later became silver stick in waiting to the Queen and commander of the Household Cavalry.

There appears to have been only a pause in the relationship with Charles, however. The Queen heard her son had taken Camilla as his mistress and that the Blues and Royals were far from happy over the cuckolding of a brother officer.

Camilla was excluded from invitation lists to formal events at which the Queen was to be present, a situation which has persisted until now. The Parker Bowleses divorced in 1995.

Charles's relations with his mother also suffered as his marriage to Diana, Princess of Wales, faltered and the relationship with Parker Bowles was revived. The prince made a televised confession of adultery and Diana lamented that "there were three of us in this marriage". She is said to have called Camilla "the rottweiler".

The Queen Mother's views put Charles in an awkward position. She was one of his most loved relations but disapproved of the divorce. In addition, she was regularly escorted to the races by Andrew Parker Bowles before her health failed.

Despite the difficulties, Camilla Parker Bowles has been painstakingly eased into royal circles since Diana's death in 1997. She gave a party in 1998 at Highgrove, Charles's Gloucestershire home, to celebrate his 50th birthday. The Queen did not go. There followed a series of events which the couple attended together but left separately.

In 2000, the year after the Ritz party, the Queen gave cautious signs of acceptance when she met Parker Bowles briefly at a Highgrove party given by Charles to celebrate the 60th birthday of former king Constantine of Greece. Eight crowned heads and a clutch of presidents were in attendance.

Full public acceptance was still some way off, however. In the same year Parker Bowles stayed behind at St James's Palace while Charles attended a party at Windsor marking several royal birthdays, including the centenary of the Queen Mother. Last year, at an osteoporosis function, the couple kissed in public for the first time.

This year the Queen Mother's death has drawn her further into the royal circle. Parker Bowles attended the funeral at Westminster Abbey where she was seated some way from the royal family with her sister and brother-in-law and two friends.

The question of possible marriage between Charles and Camilla is not yet on the agenda. Although two opinion polls published recently have shown growing public acceptance of the idea, the closest Charles has got to addressing the subject publicly came last year. "Will I be alive tomorrow? Who knows what the good Lord has planned. You can't be certain about anything. I don't know," he said.

Whatever the formalities of their arrangements in future, the presence of the prince and his mistress next month so close to the Queen at one of her proudest hours suggests Parker Bowles's days of waiting in the wings as her prince plays his royal role could be over.

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