There is a usually a market rate per mile that you are to pay to the employee when using his own vehicle. That covers current petrol value as well as wear and tear expenses. There is also the issue of time spent on the road that needs to be taken into account when calculating travelling costs and whether you’ll include it in the fees.
Current rates are £0.45/mile for the first 10,000miles, then £0.25/mile (as in 2018).
