The duty on beer is £17.32 per hectolitre per cent of alcohol in the beer.
That means that the duty on a (low-alcohol) beer with an ABV of just 1% is 17.32p per litre, which is equivalent to 9.84p per pint.
However a typical pint of beer might be around 4% ABV, so the duty is four times as high, i.e. 39.37p
The amount of VAT on a pint of beer will depend upon how much the publican charges for it. Let's suppose that a pint costs £3. About 45p of that is VAT. So the publican keeps £2.55 and hands over 45p to HMRC. However, as stated above, the price the publican paid for that pint of beer included about 39p in duty. So, in total, 84p out of your £3 pint goes to that nice Mr Darling. (If you look at those figures carefully you'll see that VAT has been charged on the duty, as well as on the actual beer. So that's a tax on a tax!)
Leaded petrol has duty charged at 57.19p per litre. If a filling station charges, say, 114.9p per litre, 17.11p of that goes to HMRC as VAT. Adding on the duty means that the government's total cut is 74.3p per litre.
Chris