The British government was in breach of the Belfast Agreement by making IRA decommissioning a precondition for progress on all other issues, the Sinn Fein president, Mr Gerry Adams, said in London last night.
Signalling his belief that decommissioning - by paramilitary groups and the British army - would not be resolved within the coming six weeks, Mr Adams said: "For my part, I believe that the issue of arms can be resolved. Indeed, enormous progress has been made in the past six years, particularly in relation to IRA arms.
"But, as I have said many times, I do not believe that the issue of arms, all arms held by all armed groups including those held by the state forces, will be resolved within the six-week artificial deadline imposed by David Trimble's contrived and calculated resignation."
Mr Adams had kept his engagement to address a group of 400 Sinn Fein activists at Central Hall in Westminster despite the structure of the week being changed by negotiations with the British and Irish governments and the pro-agreement parties at Weston Park.
If the issue of arms-decommissioning was to be dealt with properly, Mr Adams insisted, unionists and the British government must "get real" and return to the commitments that all parties had signed up to in the Belfast Agreement.
"If they genuinely want to take the guns out of Irish politics they need to understand that the arms issue can only be resolved as part of a genuine conflict-resolution process. This means it has to be dealt with as an objective of the peace process and not as a precondition to political progress."
Mr Adams said the political process could not be allowed to "falter" on the weapons issue.
Calling on the British Prime Minister, Mr Tony Blair, to "fulfil his obligations" under the agreement and deliver an accountable police force, safeguard human rights and bring about demilitarisation, Mr Adams said: "In other words, I ask him to implement the policy of his government. It means learning from the mistakes of the past and being wedded to a vision for the future. It means keeping an eye on the prize."
Sinn Fein did not understate or underestimate its responsibilities or obligations. But in focusing on the decommissioning of IRA arms above all issues, Mr Blair was responsible for "permitting a virus to remain at the heart of the agreement".
And the Prime Minister and the Ulster Unionist leader, Mr David Trimble, had made a huge mistake if they believed unionists did not have a role to play in encouraging all paramilitaries to decommission their weapons and that republicans wanted to believe the British government "is about righting wrongs".