I am helping a client with Housing Benefit overpayment. He was self employed, and used HMRC's £0.40 per mile for car expenses rather than apportioning road tax, servicing, petrol, insurance, petrol etc. between private and business use. Local authority has turned this down and asked for petrol receipts.

Does anyone know whether we can insist they use HMRC figure or does my client have to apportion all his vehicle costs?

In my view, the LA is within its rights to ask for evidence of actual costs incurred.

Under the legislation relating to self-employed earners, HB/CTB regs provide for the deduction of expenses reasonably incurred for busniess purposes. There is no direct provision for HMRC rates to be adopted although some LAs do in fact follow HMRC rates (in my experience, it is much more usual for LAs to require actual costs).

If costs include both private and business usage, these should be apportioned for HB/CTB purposes (there is settled legal authority to support this approach),

It's also worth bearing in mind some LAs will specifically ask for mileage records and, occasionally, even the last 2 MOT certificates if the LA doubts the info relating to mileage (assuming the vehicle hasn't changed).