A British government decision on the name of the new Northern Ireland police service - and the "legal description" defining its evolution from the Royal Ulster Constabulary - is believed to be imminent.
The announcement - expected today or tomorrow - is critical to determining whether Ulster Unionist Party deputy leader Mr John Taylor will support Mr David Trimble in recommending acceptance of the IRA offer to put weapons "beyond use" at Saturday's meeting of the Ulster Unionist Council.
The Secretary of State, Mr Peter Mandelson, is thought to be ready to confirm his thinking on possible amendments to the Police Bill in a final attempt to bolster Mr Trimble's position ahead of Saturday's historic vote - which both sides say is still "too close to call".
It was unclear whether Mr Mandelson would publish a government amendment to its own Bill or indicate its acceptance of an Ulster Unionist amendment.
However, with leading Sinn Fein figures warning that any further dilution of the Patten proposals could see the IRA offer to open arms dumps to inspection withdrawn, it is expected that any announcement will fall within the boundaries set by Mr Mandelson in the Commons last Wednesday.
That would suggest a formula incorporating "RUC" in the so-called "title deeds" of the new force, but not its retention in the "working title" - still almost certain to be The Police Service of Northern Ireland.
Officials appear confident that this will be enough to ensure the IRA's adherence to the Hillsborough deal, and Mr Taylor's acceptance of it on the basis that it underwrites Patten's original insistence that the RUC was not being disbanded.
Meanwhile, Mr Trimble's plan to return to government with Sinn Fein is to be challenged with an alternative set of proposals by his opponents within the Ulster Unionist Party.
The dissident UUP MP Mr Jeffrey Donaldson last night disclosed that anti-Agreement activists have been working on their own plan for devolved government which will be put to the council before Saturday's vote.
Mr Donaldson would not be drawn on the full details of the proposal except to say that it dealt "with the issue of arms and the issue of government". He said: "Nobody will be able to leave the meeting on Saturday and say they were not presented with any alternative.
"We will not be presenting an edict. We have been talking to delegates, hearing what they have to say, and will then be putting forward our own reasoned set of proposals on the basis of those discussions to members of the UUC for them to consider."
He said the package would involve the institutions already in place at Stormont. Mr Donaldson's announcement is an attempt to counter accusations by Mr Trimble that anti-agreement unionists have no alternative to Mr Trimble's deal.
The anti-agreement MP, Mr Willie Thompson, yesterday challenged the UUP leader's claim that unionism would be consigned to the wilderness if there was a No vote on Saturday.
"David Trimble is saying we are going to be in the wilderness but the fact is we are already in the wilderness. The reality is when we vote No on Saturday, we will be reaching the promised land of liberty and freedom."
Mr Trimble was engaged in strategy meetings with his supporters yesterday. His aides said they were pleased with the campaign but were not over-confident.
"A lot can happen between now and Saturday but there is a feeling that people are beginning to focus on the implications of a No vote for unionism," a source said.