I have a question about ATM skimming. If ATMs in the UK still accept magnetic stripe can't a thief still use a cloned card at the ATM to withdraw money?
Yes, they can.
If you require PIN to do any transaction, they will have your cards' information, but they can't really do anything about it.
Of course this is already bad, and it doesn't improve situation in any level. If it was a credit card that requires you to put zip code only (for example, US credit cards), then they can guess where you used credit card and punch that zipcode.
Also if you read suggested thread below, you will see how they steal PIN.
I don't live in UK, but this applies to any card reader that uses magnetic strip.
That's why card issuers are strongly recommending use of IC instead of magnetic strip.
Read this thread to avoid being a victim.