Things are hotting up in the supermarket wars and it looks like Sainsbury's have the best deals right now. Granted, the cases are smaller than in the past, but their prices are still the best currently available:
45 x 330ml bottles of Stella Artois for £20 = £1.35 per litre / 76p per pint.
45 x 440ml cans of Carling Lager for £20 = £1.01 per litre / 57p per pint.
54 x 440ml cans of Boddingtons Draught Bitter for £20 = 84p per litre / 48p per pint
24 x 500ml cans (I think) of Magners Irish Cider for £20 = £1.67 per litre / 95p per pint.
They also have 20 x 440 ml cans of Stella for £9.98 = £1.13 per litre / 64p per pint.