It seems that Virgin Mobile have finally decided to kill off the tariff I'd been happily using for the last decade or more, thus forcing me to consider the confusopoly of mobile phone tariff choices :-(
I don't use my mobile much at all (occasional texts and calls; the logs say I last used it back in August), so the old Virgin PAYG-by-direct-debit was perfect: I just paid for what I used, with no monthly charge, and I never had to worry about having to top up the phone or credit that I'd paid for expiring. I'm not sure any of the operators offer a setup like this, and certainly Virgin's current offerings seem to weigh in at 6 quid a month minimum...
Three's PAYG deal looks about the closest (catches being that you have to use the phone at least every six months, and it's not clear whether it can be set to auto-topup). Moving my number to a new provider is faff I didn't really want to have to deal with, though.
Edit: aargh, can't just switch to Three, because they only work with 3G phones and mine doesn't do that (it's a Nokia 2600 classic).