Osborne's tax cut could hit NI corporation tax plans
The ground has shifted dramatically under the Northern Ireland Executive and its corporation tax prize.
It spent years fighting for its devolution and is committed to matching Ireland's 12.5% by 2018.
When it started lobbying, the UK rate was 28%.
Now it is 20%, with the Chancellor, George Osborne, now pointing to a rate "below 15%" to woo businesses when the UK leaves the EU.
Yes, reductions in the UK make it cheaper for Stormont to implement a cut of its own.
Squeezed on two fronts
But, and perhaps more critically, it lessens the attractiveness and competitiveness of the new Northern Ireland rate.
And if Ireland looks afresh at initiatives to attract foreign companies post-Brexit, Northern Ireland could be squeezed on two fronts.
The executive has already revised downwards the jobs boost of corporation tax.
First it was 58,000 jobs, then 32,000.
Those reductions reflect cuts in the UK rate and going south of 15% would slice many more thousands off the current forecast.
The executive now faces a major challenge with its key economic policy.