Attempted to fill out an online self assessment return today and I'm just glad I'm not cleaning for a few days as I'd be concerned I might throw myself off the top of my ladder. I have a new start up business that I work on some of my days off from my full time job. I think it is the full time job that is causing the issue with the tax return. My full time job taxes me at source (PAYE) but HMRC still insist on knowing all the details for that on the tax return. The questions asked for the income as an employee are; what is your total income and how much tax did you pay. Initially I gave the total income as 36k-ish and tax 4k-ish. The window cleaning made a loss of £495 and I was asked to pay just over £1k. Couldn't understand this as I have paid all the tax due in my main job and made a loss for the self employed window cleaning. Changed the figure for the main job from 36 to 31k which was my taxable figure and the liability dropped to £50 but I can't see how I owe anything on a loss. Phoned HMRC who kept me on hold for over one hour, eventually got through to someone that said it didn't sound right but submit the return anyway and phone back in 72 hours. I look forward to being kept on hold for another few hours Friday.