The Conservative and Unionist Party

 Labour policy has always been the eventual reunification of Ireland.  Which makes problems when it needs Northern Irish members' support in the House.  There is only one thing that will obtain that support - the preservation of the Union expressed through all and every means.  The Northern Irish will take an Ulster devolved region,  and all the money and power that goes with it; they'll give concessions to obtain an acceptable level of social peace, even smile at the leaders of the IRA, even vote to prevent defeat of a Labour administration in Westminster,  as long as the Union is upheld.

Upheld, when it comes to it, by force.  By the justice and policing systems that deliver that force.  They will not permit the dissolution of the Union by the transfer of such power  from the heart of the United Kingdom state to a devolved region.  How long would the Union last then?  It would be whoops, sorry, it turned out to be a game changer, you don't want civil unrest again do you, how about an arrangement with the South of Ireland so that you're attached to both countries?  After all, we're all in Europe now anyway - time to move on.

When Brown got his votes from the Unionist Northern Irish he got them by absolute commitment to no transfer of justice and police powers.  Brown and his tactics, of course, no strategy.  Now, at the end of his misbegotten premiership, the whole power-sharing, Labour sneak into Irish reunification is about to be simply abandoned by Irish Unionists and Conservative Westminster alike.  It doesn't suit.  The Conservative party is a Unionist party.

Further:
The Irish Times reports:

'The Taoiseach and British prime minister, according to well-placed sources, proposed there should be a pre-Westminster election date for devolving policing and justice powers to the Executive. This is the long-standing key demand of Sinn Féin.

Sources said the date could be early May. This could be [in] line  with Sinn Féin demands as the British general election is expected to be called for sometime later that month.'

The insistence on a pre-Westminster election date for the transfer of justice and policing powers points to the gulf between Labour policies for Northern Ireland and the achieving of their long term Irish unification goal, and Conservative policies and their proper concern for the preservation of the Union.  To become the prime minister of a dismembered (or disintegrating) United Kingdom - a Britain  of the countries and the regions as Labour calls it -   facing the European Union, particularly post-Lisbon, would severely weaken the Conservative policy of asserting constitutional independence and self-determined consent to acceptance  of EU laws and regulations.