It's really difficult. It's like a vicious circle, you need good credit to get credit. I applied everywhere when I turned 18 and couldn't get anything. In the end I managed to get a mobile phone from 02, paid it on time every month until the contract was finished and after that I was accepted for 2 credit cards. So you could try getting a mobile. Also, www.universa.co.uk have a really high acceptance rate, my best friend got one when she was that situation. Hope this helps.