How much does the NHS spend on public health? It is an important question because, whatever the amount is, it will be hacked off the NHS commissioning budget from 2013-14 onwards and passed over to those hungry colleagues in local authorities.

To find the answer, primary care trusts were asked, for the first time, to identify in their 2010-11 accounts how much they spent on “public health” and a handy 15-page guide set out what they should include in the sums.

The results – which are trickling out as PCTs prepare to publish said accounts – are diverse. In Haringey, it seems, public health hardly happens: the PCT’s first attempt to calculate its spending came in at a measly £7 per needs-adjusted head.

That would not even cover nicotine patches for the borough’s estimated 45,000 smokers. No wonder the figures were sent back for a second try.

At the other end of the spectrum, Westminster PCT’s first count came to £169 per head; the highest in this column’s sample of 33. Also high were Southwark (£145), Blackpool (£144) and Heart of Birmingham (£106).

A conspiracy theorist might excitedly note the sizeable surpluses at a couple of those PCTs, and record that Haringey (2010-11 surplus: effectively zero) is joined at the bottom end of spending by Cumbria, which finished the year with a deficit equivalent to 2.3 per cent of its allocation.

Wandsworth, however, spoils the fun with a 2.3 per cent surplus and a stingy per head spend of just £18.

With shadow council allocations due by December, there is not much time to even things out. The 24-fold disparity in London has been sent back to the abacus, but even NHS North West’s final figures showed some spending four times the amount of others.

Intriguingly the average figure comes in at £67 a head. Applied across England, that hits 4 per cent of PCT spending: about what the Department of Health was expecting. But is this figure right?

Sally Gainsbury is a news reporter for the Financial Times.