virtual credit cards
I believe there are two available in the UK tied into a mainstream credit card.
A good one is the cahoot webcard which is 'linked' to your Cahoot credit card but generates a 'one time' card which is limited to an amount you define per transaction. This has all the info needed to complete an order but comes with a clear stop limit if you get scammed online and they can't get at your main card.
Absolutely superb for online transactions but Cahoot never seem to advertise it.