Thank you for your reply. That is reassuring and it sounds like I don't need to worry. If you don't mind I'd like to expand on a couple of details just to make sure you still think the same. As part of my assignment my employer also pays my accommodation in Scotland (they pay the rent directly to a letting agents). I have been in Scotland pretty much full time for the past 9 months with only a few trips back to London. In 3 months the assignment is over and I will return to London full time and no longer receive the per diem. Just wanted to clarify my situation as it does add up to quite a large additional sum over the 12 months.