Sitting in the front rows, well ahead of the pop stars, sporting heroes and celebrities, will be figureheads from some of the world's most controversial regimes. While Colonel Gaddafi's representative has been officially uninvited (but only after the attacks began on citizens in Libya), diplomatic niceties dictate that the representatives of other unsavoury members of the London diplomatic corps, including those of North Korea and Iran, will be welcome.
Despite Zimbabwe having withdrawn from the Commonwealth in 2003 and Robert Mugabe being subject to a travel ban and sanctions, Zimbabwe's ambassador to London, Gabriel Machinga, remains on the guest list because the two countries retain "normal" relations. St James's Palace said that all heads of mission in London have been invited as a matter of course. Diplomats and heads of state are invited by the Queen rather than the royal couple, the Palace said. A recent report for the US Congress found that, while state-sponsored abuses were at a lower level than in 2008, Zimbabwe security forces continue to beat and torture opponents of Mr Mugabe's Zanu-PF.
The presence of Prince Mohamed bin Nawaf bin Abdulaziz of Saudi Arabia and Princess Fadwa bint Khalid bin Abdullah bin Abdulrahman is also likely to draw protests. Bahraini human rights protesters are staging weekly demos outside the Saudi embassy in London against the country's deployment of troops to help quash the democracy protests there. Last month Amnesty International highlighted the case of Mohammad Salih al-Bajadi, a 30-year-old Saudi businessman who co-founded a human rights organisation, who was arrested and held incommunicado after attending a protest.
A little further along the pew will sit King Mswati III of Swaziland. It is nearly four decades since political parties and trade unions were banned; three days of planned protest to mark the occasion were called off earlier this month after most of the leadership of the opposition was arrested by the security forces and a curfew declared.
There has already been anger in his own country, where more than a quarter of adults have HIV/Aids – the highest prevalence in the world – over the absolute monarch's inclusion on the wedding guest list in London. The king, who has an estimated fortune of $100m, is no stranger to weddings: he has been married 13 times and stages an annual dance where he can choose afresh from hundreds of bare-breasted virgins. Seventy per cent of his subjects continue to live in absolute poverty, enjoying fewer rights than neighbours in Zimbabwe, and six out of 10 deaths result from Aids.
Who's in and who's out
Neither Tony Blair nor Gordon Brown has been invited to the Royal Wedding. While Prince William and Kate Middleton have sent invitations to an array of politicians, war veterans, sports stars, musicians, and charity heads, the names of the two former Labour prime ministers are missing from the guest list.
Even the landlord of Miss Middleton's local pub will have a seat in Westminster Abbey on Friday. John Haley, who runs the Old Boot Inn in Bucklebury, the Berkshire village where the Middleton family lives, said he was privileged to receive one of 1,900 invitations.
It is thought that Mr Blair and Mr Brown were not invited because they are not Knights of the Garter, members of the most senior British order of chivalry. The former Tory prime minister Sir John Major does hold the title, suggesting that he will make an appearance at the event. At the wedding of Prince Charles and Diana Spencer in 1981, all surviving prime ministers – Harold Macmillan, Alec Douglas-Home, Harold Wilson, Edward Heath and James Callaghan – were in attendance.
The 200 invited politicians and diplomats include David Cameron, his deputy Nick Clegg, the Labour leader Ed Miliband and the Commons Speaker John Bercow.
Foreign royalty invited include the Sultan of Brunei, the King and Queen of Norway and King Constantine, the former sovereign of Greece, and his wife Queen Anne-Marie. Celebrity guests will include David and Victoria Beckham, Sir Elton John, Guy Ritchie and the socialite Tara Palmer-Tomkinson.