ROYAL bride-to-be Camilla Parker Bowles said last night she was "just coming down to earth" after the Prince of Wales went down on one knee to propose to her.

The newly-engaged couple made their first public appearance together since the announcement that they are to marry.

Flashing her large, sparkling diamond engagement ring, she was congratulated on her forthcoming nuptials as the pair attended a gala dinner at Windsor Castle, where they will marry in two months' time.

Charles's long-time companion is to become a member of the Royal Family and known as Her Royal Highness - but not Queen Camilla.

Following the nuptials in a civil ceremony at Windsor Castle, she will become the Duchess of Cornwall.

But when Charles accedes to the throne as King, she will take the title of the first Princess Consort.

Clarence House made the unexpected announcement of the heir to the throne's engagement yesterday morning, prompted into action by a leak to the media.

The Queen, who gave her son and heir formal permission to marry after consulting Prime Minister Tony Blair on Wednesday, joined the Duke of Edinburgh and Princes William and Harry in congratulating the bride and groom-to-be.

William and Harry said they were delighted for their father and new stepmother.

The Archbishop of Canterbury was involved in the negotiations about how Charles should marry divorcee Camilla, with whom he had an affair while he was married to Diana, Princess of Wales.

The civil ceremony, for mainly family and friends, is to be followed by a religious blessing with the Archbishop in St George's Chapel.

The announcement of the engagement comes nearly nine years after Charles divorced Diana, and more than seven years after she was killed in a car crash in Paris.

The inquest into her death has yet to be completed, and former head of the Metropolitan Police, Sir John Stevens, is still investigating the 1997 incident.

Although upon her marriage to the Prince of Wales, Camilla will be technically the Princess of Wales, aides said she wished to be known as the Duchess of Cornwall for private reasons.

But there can be no doubt that the public's opinion on her adopting the title that belonged to the "People's Princess" Diana was a major factor.

About seven out of ten people registered opposition to the marriage in two polls conducted yesterday.

Voting figures in a Teletext poll at lunchtime yesterday showed that as many as 72 per cent of viewers were against the match.

Meanwhile, ITV1's This Morning programme asked viewers whether Charles and Camilla should marry, with 68 per cent voting no and 32 per cent in favour.

The prince was said to be in marvellous spirits following the announcement. "Mrs Parker Bowles and I are absolutely delighted. It will be a very special day for us and our families," he said.

Welcoming the news, Mr Blair, said that he and the Cabinet had sent the couple their congratulations on behalf of the Government.

"We all wish them every happiness for their future together," he said.

The former Bishop of Durham, the Right Reverend David Jenkins, said: "My immediate reaction is 'about time too'."

Vera Baird, Labour MP for Redcar and Cleveland, said she was delighted by the news, adding: "Everyone knows they are in a long-term relationship and nothing ought to stop anyone from marrying if that's what they want to do."

But not everyone was so impressed.

Kevan Jones, Durham North's Labour MP, said: "I've got no interest in this whatsoever.

"And I'm sure the majority of my constituents haven't either."

Senior officials denied the pair were pressured into marrying following controversy over how the prince funded his partner's lifestyle.

"This issue of marriage has been considered for a long time," an aide said.