Blockchain.info just launched a way to buy BitCoins with £ GBP using the new Barclay app PingIt which links to your bank account. You simply tell the website how much £ you will transfer and it says the current BTC price. It gives you the phone number, and a reference number which you need to put in the message.
It then appears as BitCoins like an hour later. Best way ever in UK, it's what I have been waiting for, just launched and fantastic!
https://blockchain.info/wallet/deposit-pingitYup, loving this - demo'd it live yesterday to a bunch of people who had never seen Bitcoins before, really adds a wow factor.
Limits: You have to transfer at least 10 GBP per go, and you can only buy a maximum of 250 GBP per week.