This has become an extremely complex area in recent years and a recent tax case, concerning a consultant, which restricted mileage claims, will have repercussions for sessional GPs.
First of all – what journeys are allowable for GP travel expenses?
Salaried GPs may claim for journeys undertaken wholly in the performance of their duties. Where the practice reimburses a doctor for visits (pretty rare!), then reimbursements up to 45p per mile (assuming less than 10k miles per annum) are tax free. Payments in excess of that (sometimes seen in payments by hospital trusts) will be treated as taxable benefits and should be shown on form P11d at the end of the year, and must be recorded on the employment pages of the tax return.