One person who would never have dreamed of missing today's celebrations is Margaret Tyler from Wembley. She is so obsessed with the Royal Family that she could lay claim to the title of London's - if not Britain's - biggest royalist.
Among the crowds on The Mall today there will have been many people claiming that they're the greatest royal fan. But that title must surely belong to Margaret Tyler who has the biggest collection of royal memorabilia in the country - more than 10,000 items.
London Tonight's Business Correspondent Glen Goodman reports: