The decision was given overwhelming support by MPs on both sides, and was greeted by cheers when it was announced.But there are fears that excluding the two republicans will be used as a propaganda weapon to boost their support.
They are due to turn up at the Commons, probably on Tuesday, to demand entrance and to argue that the decision discriminates against their electors. Republican sources have already made plain their intention to open a London office, either inside or outside the Commons.
Tony Blair, the Prime Minister, later said he wanted to make progress on the Ulster cross-party talks, but he repeated that Sinn Fein would not be admitted unless the IRA declared "an unequivocal ceasefire demonstrated in word and deed."
Mr Blair is due to set out a definitive statement of his policy during a visit to Northern Ireland this week. He said there would be no question of any change to the status of Northern Ireland without the overwhelming consent of the people of the Province.
Martin McGuinness said: "There may be legal avenues we would need to explore. We reserve judgment on all of that until we have the full statement. Mr Adams added: "It isn't the end of the world. Part of the silliness of this is that Sinn Fein is in no way dependent on the facilities, but we do have a right to them."