A persistent bug in the PAYE system is caused by the HMRC computer creating a duplicate employment record which it then uses to demand PAYE for wages which have not been paid.

The traditional way to hide sales from HMRC is to take payment in cash and not put it through the books. Nowadays technology helps dishonest traders to hide sales by using electronic sales suppression (ESS) software.

Student loan repayments (SLR) are normally deducted under PAYE from employment income so many people incorrectly assume that SLR are not due on other 'unearned income' such as rent or pensions.

When purchasing commercial premises you need to know whether VAT will be added to the price as the stamp duty land tax charge (or similar taxes in Wales or Scotland) is calculated on the VAT inclusive value.

For a medical service to be exempt from VAT it must generally be performed by a registered health professional or a staff member who is directly supervised by a registered health professional.

The amount of your state pension is largely determined by how many years of NIC you have completed during your working life. You can check your NIC record in your online personal tax account (www.gov.uk/personal-tax-account).

The changes to the pension rules announced in the Spring Budget were designed to dissuade higher earners from retiring early to avoid pension charges on high contributions but the new rules could have the opposite effect.

Petrol and diesel pump prices are high but the tax-free mileage rates payable to employees who use their own vehicles for business have not been adjusted for over a decade.

Occasionally you may reward your employees with something special such as a holiday or a hamper. If the value exceeds the tax-free amount permitted under the rules for say long service awards, trivial benefits or staff suggestions it will be taxable.