The Value Added Tax (Input Tax) (Reimbursement by Employers of Employees' Business Use of Road Fuel) Regulations 2005 No. 3290

4.  Where only part of the road fuel is used for the purposes of the taxable person’s business, by payment of either—

(a) an amount which represents the actual cost of the road fuel so used determined by—

(i) the total distances travelled by the vehicle in which the road fuel is used for the purposes of the taxable person’s business; and

(ii) the cylinder capacity of that vehicle; or

(b) the actual cost of the road fuel in circumstances where the taxable person will account for output tax on any private use under section 57 of the Value Added Tax Act 1994.