The credit crunch is heading your way. While the government has so far rejected the idea of revisiting its health spending plans up to 2011, there are numerous other ways it can get its hands on trust cash.

The problem for the NHS is that it is the only part of the public sector which is squirrelling away reserves by the hundreds of millions. Compare this with the Ministry of Defence, stretched to its limits, and local government, locked in a cycle of topping up inadequate grant increases with inflation-busting council tax rises.

Meanwhile primary care trusts struggling to keep their surpluses down have resorted to wheezes ranging from paying for up to£300m of this year's acute costs out of last year's cash to moving the costs of hearing aids from the capital to the revenue account.

Inevitable scrutiny

As tax receipts fall and the Treasury struggles with financing the bank rescue plan, it is inevitable health spending will come under renewed scrutiny.

While the increase in NHS spending has outstripped increases for the rest of the public sector every year since 1997, productivity has fallen. The combination of record spending increases, high and growing reserves and falling productivity is unsustainable.

Foundation trust surpluses might be first in the firing line. The small print could allow the DH to claw them back if the state of wider public finances justifies it.

PCTs will be under pressure to lift their game in using commissioning to drive efficiency and quality - which should go hand in hand. Judging by today's annual health check data, many are a long way from being ready to meet that challenge.

And whatever happens in the short term, there is the prospect of no real growth in health spending in the years after 2011. More trusts failing as money tightens is just one possible consequence.

The challenge for managers and the NHS leadership will be to keep focused on reform - quality, safety and choice - as the financial waters get rougher.