No! Not like that!
Don't worry, I'm not going to put my SIM into a dongle or anything naughty like that.
As a purely hypothetical question - what I'm thinking is this: calls to 0800 numbers are free, right? What if, theoretically speaking, I dialed into an ISP with an 0800 access number, using the mobile as a Bluetooth dial-up modem?
Allowed, or not allowed?