The guest list for the royal wedding sparked controversy on Sunday after monarchs from countries with poor rights records were invited but two former prime ministers were not.
Rights groups criticised Prince William and Kate Middleton for inviting foreign royals from Bahrain, Swaziland and other nations where authorities have violently suppressed pro-democracy protests in recent weeks.
Newspapers pointed out that Labour ex-premiers Tony Blair and Gordon Brown were snubbed on the list, which was released on Saturday, while former Conservative leaders Margaret Thatcher and John Major were invited.
"Labour MPs will not be alone in thinking it odd the two former occupants of Number 10 (Downing Street) have not been invited to the wedding," the Sunday Telegraph commented.
Royal officials said Blair and Brown were not invited because unlike Major and Thatcher they are not Knights of the Garter, Britain's highest honour.
St James's Palace, William's office, said the wedding was "not a state occasion so there is no reason why they (Blair and Brown) would be invited," the Sunday Telegraph reported.
Major -- who was prime minister from 1990-1997 and acted as a guardian to Princes William and Harry after Diana's -- will attend, but Thatcher who was in power from 1979 to 1990, has declined on health grounds.
Less controversial attendees at Friday's wedding in Westminster Abbey include footballer David Beckham and his fashion designer wife Victoria, musician Elton John and "Mr Bean" actor Rowan Atkinson.
But there was surprise when royal officials announced that Crown Prince Salman of Bahrain would also attend.
Earlier reports said the Gulf state's rulers would withdraw to avoid embarrassment after a bloody crackdown on protesters there left at least 24 people dead.
Anti-monarchy campaign group Republic hit out at inclusion of royals from not only Bahrain but also Saudi Arabia, Oman, Brunei, Qatar, Swaziland, Lesotho, Bhutan and Kuwait.
"This guest list reads like a 'Who's Who' of tyrants and their cronies," Republic chief Graham Smith said.
"Whatever happened to William's supposedly strong social conscience? He must take personal responsibility for this and rescind the invitations immediately."
Leading gay rights campaigner Peter Tatchell said the invitations of "royal tyrants" from Bahrain, Swaziland and Saudi Arabia were a "massive misjudgement".
St James's Palace said it had sought advice from Britain's foreign ministry on guests from abroad.
"Invitations are extended from the queen following the long-held tradition of inviting other crowned heads of state, we have taken advice from the Foreign Office about their continued inclusion on the list," a spokesman said.
Swazi demonstrators were planning to demonstrate on Tuesday outside the Dorchester hotel in London on Wednesday, where the country's King Mswati III will be staying, South Africa's Mail and Guardian newspaper reported.
But Archbishop of Canterbury Rowan Williams, the head of the world's Anglicans and the man who will marry William and Kate, said in his Easter sermon on Sunday that the wedding was a cause of "shared celebration."
"It's nice and entirely appropriate that we are being encouraged to some public displays of shared celebration next Friday: let a thousand street parties blossom," he said.
Five days before the wedding, Queen Elizabeth II and many other senior royals had something of a "warm-up" with an Easter service at Windsor Castle, near London -- although William and Kate did not attend. www.mannamart.com