Pay as you go in mobile broadbands?

Hi, I'm going to live in London in a few months. I need to keep in touch with my old company through internet.. but I don't know if I'll have a reliable internet connection in the share(s) room(s) that I'll rent.
So I've thought to take a mobile broadband, but the mobile companies will probably ask for a bank account (I don't have it yet) or a english address.. while I get everything I need, I want to be able to connect with my old company. So, a tamporal solution could be something like a 'pay as you go' SIM Card for internet.
Is there any solution for that?

Thanks!!!

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