[tay77]

Not sure when you're going, or if you want a Single or Return, but I've found an £18 single (funfare) and a £45 single ("normal fare") on National Express.

I've also found a single on Megabus.com for £11...


Edit: I've just checked on bmiBaby, and you can get a single flight for £4.49 (£23.44 with taxes).


(Note - As I said, I don't know when you're travelling, so I've inputted the date as Sat 17th May, so will probably be more expensive if you're going sooner).