I have taken on a new client. They asked me whether an item of expenditure which the previous accountant wouldn't include was allowable or not. In my opinion it was. I would have no problem in claiming the expenditure in the current tax year. However what is the best way of claiming back past expenditure. I was thinking of including all past expenditure in the current year and covering myself with a note in the tax return even though I suspect that notes are never read by HMRC. The alternative would be to write to HMRC which in the current climate might take a very long time and involve alot of long drawn out correspondence with HMRC. What would you do?