UK economy: Why is it shrinking?

Latest official figures show that the double-dip recession in the UK has deepened.

In the second quarter of the year, that is, between April and June, the output of the economy shrank by 0.5%. This decline has shocked many, although it is better than the original estimate of 0.7% contraction.

But what is behind that number? Are there any brighter points and which sectors of the economy are being hit hardest by the downturn?