Taking their toll

SIR – Although the tolls at the Dartford Crossing (Letters, September 5) are collected through a website operated by the Government, the day-to-day operations are run by Société des Autoroutes du Nord et de l’est de la France (Sanef).

I doubt that they do this for nothing. What percentage of the tolls collected actually goes to the Treasury? Sarah Duke-woolley

Ingatestone, Essex