I’ve always been under the impression that you can claim tax relief against the difference between whatever you are paid for business miles and the HMRC mileage rates

But speaking to someone recently who said their accountant stated they could claim 100% of the difference and not just tax relief at the marginal rate – anyone else heard this?

I’ve always been under the impression that you can claim tax relief against the difference between whatever you are paid for business miles and the HMRC mileage rates

That’s as I understand it. If your company only pays you (say) 15p a mile I can’t see HMRC paying you an extra 30p a mile (given the 45ppm HMRC allowance for the first 20k miles)

I think you’re correct. You can claim tax relief on the difference between what you’re paid (e.g. 20p per mile) and the HMRC rate (45p per mile for the first 10k miles this year (40p last year)). So 40% (if you’re a higher rate tax payer) of 25p per mile.

This is what I do, and I just got my tax rebate a few days ago.

EDIT: From the HMRC website – If the Mileage Allowance Payments you pay are below the approved amount for the tax year – your employee will be able to get tax relief (called Mileage Allowance Relief, or MAR) on the unused balance of the approved amount

As Cheshirecat said. Claim for it under employment expenses if you submit a tax return or put a claim into HMRC using P87 form.