I went through in my swiss registered car and thought about not bothering with the now exorbitant £2.50 charge. They make £1/2 million per day!!!

In the end I decided to ring them and pay. As usual you get press 1 for this 5 for that. When you eventually get through I paid. I asked them what happens with foreign vehicles and non payment. The told me....'a warning letter will be sent out permitting 14 days to pay without extra fines.'. After 14 days the fines start.

Last year I received a french speeding fine. They had no trouble looking up my swiss address. The European wide Erasmus database is shared automatically apparently.

If I had known, I would have waited for the warning since it is risk free. On their website they say they use european debt recovery agencies. Mind you, sending a warning letter is going to cost not far off £2.50, so would they really bother? I would be interested to hear non payers' experiences especially of the dartford crossing.