Record Keeping for Tax Purposes

HMRC has produced a guide which includes details on the bookkeeping requirements for the purposes of Self Assessment.   

Some expenses have an element of private expenditure and need apportioning before you make a claim. HMRC will accept claims for business use of telephones, cars and rooms used as offices, studios etc.

It's advisable to keep all records, receipts or invoices for a minimum of five years and 10 months following each tax year. This includes telephone bills, receipts for car repairs, servicing and insurance, plus household bills for council tax, insurance, maintenance and repairs etc.

It is unrealistic to expect taxpayers to log every telephone call and keep an exact record of business mileage, but any valid evidence you have for the amount claimed is very useful. Logging telephone calls, business mileage and evidence of journeys for a sample period could be very helpful indeed if there was a dispute about the amount claimed.

It will not be considered good enough to claim an estimated percentage without some evidence; these claims will be an open invitation for an HMRC enquiry.