So currently i get a company car with fuel card covering all private miles etc.

We do have an opt out option but with my main place of work being a 42mile commute each way my "private" miles are quite so opting out of the fuel card is probably daft.

My question being - currently i pay a fixed fee for the fuel card based on the car. If i opt out of the car but keep the fuel card - how does the tax then work?

Thanks
Lee