Yes, I do quite a few miles for work in my car (over 700 business miles last month).
40p/mile for 10k and then 25p/mile are the HMRC approved rates.
http://www.hmrc.gov.uk/rates/travel.htm
AFAIK… Your company can chose to pay you more than these figures but you are meant to pay tax on the amount above the approved rates. If you are paid less, you can claim tax back.
Via my MP, I’ve previously tried to find out why HMRC haven’t reviewed these figures. My information is at home, but IIRC the approved figures date from when fuel was something like 80p/litre, not £1.20 or more.
HMRC gave me a BS response and I’ve not got round to annoying them further about it.