I'm a higher rate taxpayer paying income tax under PAYE. I create courses and sell these online. Will I have to complete a tax return to report any extra income I make that is in addition to that reported by my employer (under PAYE)? Income at first will be very low, £100-£200 a month I estimate. Can I deduct various expensesfrom my profit,so that I pay less tax such as a portion of the mortgage; a laptop; training to give me the technical knowledge to create the courses?

Arthur Weller replies:
If the net income (i.e. gross income less allowable expenses) will be less than £2,500 per year, you can apply to HMRC to adjust your PAYE code number so that the income tax can be collected in this way. You can deduct certain allowable expenses from the gross income, as above. With regard to your mortgage, see: www.gov.uk/hmrc-internal-manuals/business-incomemanual/bim47820. As for training courses, see: www.gov.uk/hmrc-internal-manuals/business-incomemanual/bim35660. Expenditure on a laptop is probably capital, for which capital allowances are available (possibly the ‘annual investment allowance’).