However, it seems that I can get 250 minutes and 1GB of data for £10/month from both Tesco and GiffGaff.
GiffGaff are run communally, and seem to have a nice spirit. However, they have also had a couple of major outages and their message boards are awash with people having issues. And as far as I can tell their bulletin boards are where you're supposed to get support.
Tesco are possibly going to be more efficiently run. But on the other hand aren't fluffy. And their bank computers managed to completely fuck up in the middle of last year, so it's not like they're immune to issues.
Both of them use O2's network. And, of course, are both cheaper than O2.
So now I'm not sure whether to toss a coin, or what.
Original post on Dreamwidth - there are comments there.