Gerry Adams, president of Sinn Fein, and Martin McGuinness, the party's chief negotiator, declined because the heir to the throne is the Commander- in-Chief of Britain's Parachute Regiment. Republicans have always reviled the regiment for its involvement in "Bloody Sunday" when British troops killed 14 Catholics during a protest in Londonderry in 1972.
About 1,000 guests, including the 18 Northern Ireland MPs, have been invited to this week's garden party at Hillsborough Castle. The event is one of the major dates in Northern Ireland's social calendar. The Secretary of State for Northern Ireland, Mo Mowlam, said that she had included the two leaders of the IRA's political wing on the guest list because they had signed up to the peace accord.
However, she had known there was a strong possibility that they would turn down the invitation, saying before receiving their replies: "They are republicans, they are not supporters of the monarchy." Mr Adams and Mr McGuinness have never taken up their seats in the House of Commons because they refuse to swear allegiance to the crown.
The decision to invite the two Sinn Fein MPs angered many Unionists and Opposition MPs. Ulster Unionist MP Ken Maginnis said: "I believe this is yet another insensitive decision by Mo Mowlam." Andrew Hunter, vice- chairman of the Tory backbench committee on Northern Ireland, said: "These men are apologists for the murderers of the Prince of Wales's uncle. It is dreadful that the Sinn Fein leadership should be given the mantle of respectability when no weapons have been decommissioned."
Andrew Mackay, shadow Secretary of State for Northern Ireland, said: "The simple truth is that an invitation like this puts the fear of God into the Unionist community. And the danger is they will react by actually electing Unionist politicians who will be there to wreck or disrupt the assembly which will not be in the interests of a lasting settlement."
Fifteen police officers and four civilians were injured on Saturday when rioting erupted in the Garvaghy Road area of Portadown, during an Orange Order march.
At one stage during the six hours of disturbances, a mob of up to 400 rioters attacked officers with petrol and blast bombs. Police responded by firing plastic bullets. It was the first major outbreak of street disorder since the Good Friday peace agreement.Reuse content