A while ago I looked into this for my son at University. The only way we worked out you could do it was by connecting a mobile phone to a laptop (Expensive connection kit!) then use a dial up connection to access the Internet (Very Expensive phone bill).
While I found that it was possible the huge costs of using a mobile phone on a dial up account stopped me from going any further into this.
If you are still determined to go ahead I would checkout the options along these lines.
You will to find a connection kit.
You will need a UK dial-up ISP.
You will need a large bank balance!!!!!!