Transferring between offices/locations?


Hi all,
Once you start with a Big 4 firm (say, KPMG) at a specific office, as a graduate recruit, how difficult is it to transfer to another office/location - for example from Leeds to London? Is this common practice, or do firms generally frown upon this? How long do you have to be with the firm before you can switch, if at all?

Any thoughts would be greatly appreciated!