No 10 described the Prime Minister's meeting with Peter Robinson, Northern Ireland's First Minister, and Martin McGuinness, his deputy, yesterday as constructive.
However, they emerged expressing disappointment that Mr Cameron had made clear there would be no decision on devolving corporation tax to Stormont until after the 2014 Scottish independence referendum.
Mr McGuinness said: "It's very, very clear from the meeting that the whole issue of the referendum in Scotland is playing in big time to this debate on corporation tax.
After being floored by a linguistic uppercut from Scots broadcaster Eddie Mair, the tousle-haired Mayor could have been forgiven for throwing in the towel and spending Easter on a far-flung island watching Yes Minister videos.
Yet while his father branded Mr Mair's inquisition as the "most disgusting piece of journalism I've listened to for a very long time", Johnson Minor was more charitable.