Why is the government borrowing so much? My answer is that it's because the private sector is lending, so someone must borrow. If you're not happy with this answer, though, and want a more conventional view, take a look at tables PSF3 and PSF6 of today's figures (pdf) on the public finances. I've reproduced highlights below.

For me, four things stand out here.

1. Dole payments account for only a small fraction of the rise in borrowing. Comparing the fiscal year so far with the same period last year, social benefits have risen by only £7.4bn. That's less than one-fifth of the increase in borrowing.

2. Government spending, excluding interest and social benefits, has not increased much. It's up by 5.9 per cent on the same period last year. This is actually less than its average annual growth (6.8 per cent) over the period 2002-03 to 2007-08. So much for Keynesian counter-cyclical fiscal policy.

3. Only a small part of the increased deficit is due to recent policy decisions. The Treasury estimates that policy moves in the Budget and Pre-Budget Report, such as the cut in VAT, would add £20.8bn to this year's deficit. Assuming this is spread evenly over the year, it accounts for only around a quarter of the difference in borrowing from last year to this.

4. A bigger part of the rise in the deficit is due to lower tax revenues. Falls in income and corporate tax have done almost £10bn more damage to the deficit that Darling's VAT cut.

One reasonable inference here is that much of the increased deficit is due to the weak economy causing tax revenues to collapse. It doesn't follow automatically from this that a return to growth will restore the public finances: if a man has been hit by a bus you cannot return him to life by reversing the bus. But one can be forgiven for taking the view that it's worth seeing what a return to growth will do for the public finances before deciding whether or not to take big policy measures.