By Mark Devenport BBC Northern Ireland political editor

There's been a lot of talk about whether Northern Ireland is a cold house for nationalists or a cold house for unionists.

One thing is for certain. This week it was a cold house for everyone.

The weather doesn't normally have a direct impact on politics.

But ice at Belfast International airport and snow at Heathrow prevented some MPs attending the first Northern Ireland Questions of the year and delayed Sinn Fein's talks at Downing Street by 24 hours.

If it hadn't been for the snow, Gerry Adams and Martin McGuinness would have been and gone one day ahead of the IRA's New Year statement.

Gerry Adams held talks with the prime minister

As it was they had to explain to the prime minister why the organisation thought demands for its disbandment were "unacceptable and unrealistic".

On the face of it, the IRA's comments might have looked like a slap in the face for the government.

But maybe the Sinn Fein politicians pointed out that the adjectives weren't all that different from those deployed in the IRA's previous statement in October.

So it was just business as usual.

In fact government officials regard recent meetings as "pretty positive" and there's a sense that republicans are on for some kind of deal, although the devil may well be in the detail.

Irish sources hope that by March there could be some substantial disarmament accompanied by indications that the IRA's war is over and that the organisation is standing down.

Sinn Fein's support for the new police service would be part of the mix, although the party isn't expected to take places on the Police Board until after an election.

Violence monitor

Trust is in short supply, however, so there's discussion of some kind of verification mechanism for any 'acts of completion' which do take place.

For Ulster Unionists that means a return to the idea of a paramilitary violence monitor, already promised by Paul Murphy's predecessor John Reid.

For nationalists, there's the option of an outside guarantor of any new agreement.

Irish diplomats have floated the idea of an oversight commissioner - similar to the one already appointed on policing - who would keep an impartial eye on which aspects of the Good Friday Agreement have been fully implemented.

If Voltaire's Dr Pangloss was chairing these discussions then "everything would be for the best in the best of all possible worlds".

But given that we are talking about Northern Ireland there are plenty of flies in the ointment.

The loyalist feud of recent weeks and the re-imprisonment of Johnny Adair underlines the unpredictability of events.

This week saw the loyalist Progressive Unionists pull out of the multi party talks - a strong indication that loyalists don't intend to participate in any "acts of completion".

With loyalist guns far from silent, some IRA commanders will be reluctant to countenance talk of "standing down".

On the wider front there's the question mark over David Trimble's ability to deliver unionism in the run up to an election which could assist the DUP and sceptics within his own party.

So there's still a great deal to play for during what Martin McGuinness has described as the most critical six to eight weeks in the past 80 to 90 years.