If Northern Ireland does not fall into line with Westminster on welfare reform it will cost us more than £1bn in funding over the next five years, as well as 1,410 Civil Service jobs in Belfast and Londonderry, according to a Stormont minister.
The potentially ruinous figures are contained in a paper circulated by Finance Minister Simon Hamilton (below) to all his Executive colleagues.
Britain will starting switching off its old IT infrastructure as it moves towards the new benefit system. If separate systems were needed here, the cost by 2019 would hit an estimated £1.8bn.
In his letter, a copy of which is held by the Belfast Telegraph, Mr Hamilton warns that the £15m cost in the first quarter of this year "could have been allocated to local schools, hospitals and roads".
He doesn't mince his words as he attempts to push his ministerial colleague over the line in time for the next Executive meeting, which is scheduled for Thursday.
He writes: "It is imperative that the delay in welfare reform is brought to a conclusion at the next Executive."
Welfare Reform in Britain will be rolled out over a number of years and our block grant will be reduced accordingly and the cost will rise every year until it reaches a peak of £343m by 2018-19.
The cost between now and then will be £1,061.9m, which must be found by cutting other budgets or raising local taxes.
This year it will cost £105m.
Mr Hamilton warns that this will mean cutting public services and, he writes, "represents the annual costs of providing 2,500 nurses or 2,100 teachers".
He argues that if Northern Ireland attempts to go it alone by breaking parity on welfare, the jobs of 1,410 people employed by the Social Development department could be under threat.
These civil servants, working in bases in Belfast and Derry, provide back office services for "child maintenance and social security services to people in England on behalf of the Department of Work and Pensions" (DWP), a UK ministry.
He revealed that the DWP has "already indicated that should Northern Ireland fail to maintain parity in the social security system it will relocate the work to other DWP centres in Great Britain."
STORY SO FAR
The British Welfare Reform Act received Royal Assent nearly two years ago, but since welfare and benefits are a devolved matter it cannot be extended here without Stormont's agreement. Sinn Fein and the SDLP are currently resisting the change because the new benefits system involves cuts. However, we would have to make up the shortfall if the cuts are not imposed.