This is a cracker for pizza lovers.
Choose any main dish (including pizza) for only £5.
In theory you have to be an O2 customer, but I heard it can be done with a free PAYG sim..or even another network
If you don't want to get a free sim, you can simply ask other diners if they have an O2 phone and to sort you out for that visit..
Best to order a jug of water to sink it all down, as soft drinks are usually quite dear (£3 for a Coke)..
There are no limits to the number of uses. Also valid on take aways..