I had this years ago, the cars we were driving would only do about 25 to the gallon and we could claim 10 or 11p per mile, so you ended up paying towards your business mileage also.
Funny how that car kept breaking down

but saying that when it was OK the journey's suddenly gained a few miles here and there too
One guy went as far as to disconnect the speedo at weekends put a 12v motor on and actually add miles so he could claim them back
