Yet the congregation is a very odd bunch. Until this morning, when the Foreign Office belatedly withdrew his invitation, there was room for the Syrian ambassador Sami Khiyami, whose President Assad is busy ordering his troops to fire on his own people. However there is no place for Tony Blair, the man who arguably saved the monarchy from self-destruction nearly 14 years ago. Nor is there a spot for the other great redeemer, Gordon Brown who pushed for Diana's memorial - a poisoned political chalice if there ever was one - as the dust settled over the worst week for the royal family.
Let us remind ourselves that it was Blair, whatever his faults, who gentled the Queen and the rest of the royal family to return to London from their Highland retreat during the universal mourning after Diana's death. It was his right hand man, spin doctor Alastair Campbell, incidentally there is no place for him either, who took the palace courtiers by the scruff of the neck and forced them to face up to their obligations to the British people
Anyone who was there at the time remembers how ugly and genuinely out of hand things were getting. At planning meetings between Downing Street and Buckingham Palace to discuss whether the boys should walk behind the funeral cortege, there were genuine fears that if Charles walked without his children with him he would be attacked by outraged members of the public.
The then Prime Minister, who dreamt up the immortal phrase 'People's Princess, was instrumental in keeping the royal roadshow literally on the road. Months later Gordon Brown as Chancellor of the Exchequer helmed the tricky discussions about how to best celebrate Diana's memory. A political minefield if ever there was one.
The result of their work; no room at the Abbey for two men, dragooned into royal service, who saved the House of Windsor from itself. Maybe the representatives of North Korea, Iran, and Zimbabwe - hardly great friends and admirers of Britain - can save them some wedding cake.