Saw today in the Maidstone Poundland 2x5 packs of Philips Enery bulbs for £1.
They come in Screw or Bayonet fittings, 11watts (60w equiv).
May not be nationwide, but the Maidstone store had a lot of them in a stand by the tills.
Now found this deal was posted 2 months ago, so don't flame me for a repeat post (nothing came up during the intial search for 'poundland')!!!!!!