Home Office ministers could have given approval to the first merger of two police forces this week - but only if they'd agreed a year-on-year cost of around £13-£15 million. Peanuts in Whitehall terms, but if they'd agreed to that then everyone else might have demanded the same, leaving a hole in the police budget.
The costs of the ID card scheme are, of course, vast in comparison. So vast that the Tories think that they can make a whole series of promises simply by pledging not to spend billions on ID cards.
I am not alleging that the Treasury are behind the go slows. The Home Office budget for the next three years was agreed some time ago. No effort has been made, I'm told, to re-open it. Team Brown were not asked their view on police mergers. Had they been they would have said that they hoped spending money now would produce long term savings.
My suspicion is that the home secretary - who unveils his reforms of the Home Office next week - is looking for things that will restore confidence in his department in the short term, and to postpone rows that are costly - not just in political terms but in financial terms too.
This may be the first example of a minister in a very high profile department having to get used to living on budgets that are much tighter than they've been at any time since Labour came to power.