20,000 fans hail The Queen at 80

WINDSOR - The Queen was given a rousing reception by 20,000 fans when she went on a walkabout to celebrate her 80th birthday.

Waving Union Jack flags and clutching bouquets, wellwishers launched into an impromptu chorus of "Happy Birthday" as the beaming monarch stepped through Windsor Castle's Henry VIII gate to mark her octogenarian milestone.

Police put the numbers at over 20,000, a bigger turnout than the crowd for the wedding last year of Charles to Camilla, Duchess of Cornwall, after a 35-year romance.

With a decade to go before she rivals Queen Victoria's 64 years on the throne, the sprightly working grandmother shows no signs of slowing down and she has genes on her side -- her mother died at 101.

Crowned nearly 53 years ago, Europe's longest-serving monarch has ruled out abdication and opinion polls show republicans face a losing battle calling for the abolition of the monarchy while she is alive.

Ardent royalists pressed forward 10-deep against the crash barriers to offer their congratulations as the broadly smiling Queen, wearing a fuchsia coat and feather hat, spent 45 minutes working the crowd.

"I am a fervent royalist. She will surely beat Queen Victoria's record. I am sure of that," said Jennifer Hawkins, clutching an inflatable corgi dog in honour of the Queen's favourite canine.

Wheelchair-bound American Julia Real, who flew in from New York to share her own 80th birthday with the Queen, said: "The best present for me is to see her."

Welshman Colin Edwards, sporting a Union Jack T-shirt and holding a birthday poem he specially wrote for the Queen, said: "I've now done four royal weddings and two funerals. This royal watching really is like a drug. The adrenaline is amazing."

The Queen, who has seen 10 prime ministers take office during her reign, opted for a low-key day of celebrations.

On Friday evening, Charles hosted a candlelit family dinner party for his mother at the newly refurbished royal palace in the historic Kew Botanic Gardens.

She was flanked at the dinner of roast venison by Charles and his eldest son William. Afterwards the royal family were treated to a firework party that lit up the night sky.

Charles, who hailed his mother in an emotional public broadcast as a "figure of reassuring calm and dependability," is much closer to her now that his tangled love life has been sorted out.

His first wife, Princess Diana, killed in 1997 in a Paris car crash that provoked an outpouring of grief from Britons, had blamed Camilla for the breakup of her marriage to Charles.

The Queen suffered a backlash from her children's disastrous marriages but now polls show that public opinion is broadly pro-monarchy -- at least until she dies.

In an ITV News survey, Elizabeth was rated the most popular royal. Bottom of the survey came Camilla.

More than half of those polled felt Camilla should not become Queen when Charles finally accedes to the throne.

- REUTERS