When you're filing a self assessment tax return, you can claim for certain expenses to help bring down your tax bill.

In general, when the taxman talks about "allowable expenses", he means things that were necessary to keep your business running. Not every cost counts as an "expense", though, and not every expense is allowable.

The rules trip a lot of people up, leaving them stuck with a ramped-up tax bill or in hot water with HMRC. RIFT's tax return service is all about keeping the taxman in his place and off your back. If you feel him breathing down your neck around tax return time, here's a rundown of some often-forgotten expenses.