Queen Elizabeth launched her 80th birthday celebrations yesterday by hosting lunch for 99 people born on the same day as her.

The guests, who all share their birthdays on April 21, 1926, were picked for the Buckingham Palace lunch by ballot in January.

Elizabeth has been on the throne for nearly 53 years and any suggestion that she might contemplate abdication was firmly squashed yesterday by her cousin who said she believed the monarch would never retire. Margaret Rhodes said she did not believe abdication was an option for the sprightly monarch.

“I’m perfectly certain she will never retire as such because it’s not like a normal job,” she told the BBC.

“It’s a job for life and to the Queen the vows that she made on Coronation Day are something so deep and so special that she wouldn’t consider not continuing to fulfil those vows until she dies,” she added.

The Queen’s actual birthday falls on Friday and she will mark the occasion with a walkabout outside Windsor castle. Her eldest son and heir Prince Charles is hosting a private family dinner for her.