The Liberal Democrats at their conference today have come up with the barmy idea of” hugely increase investment in the railways, paid for by introducing motorway tolls for lorries” Plans also include “Setting up a Future Transport Fund to invest in key rail and light rail improvements and extensions, including High-Speed Rail, by using the proceeds from charging road freight for using the motorways and the proceeds from a climate change charge on air flights within the UK, exempting ‘lifeline’ flights.”

They obviously don’t understand that lorries already page huge amounts of tax through fuel duty and VED. Much of that already goes to the railways.

And it has obviously escaped them that there are only 420,000 trucks on the road compared to 28 million cars. Trucks alone will never be able to pay enough money for such a “huge investment” in rail.

It is true that the German “Maut" (toll) does raise considerable sums from truck operators, which is meant to fund transport projects. But Germany has many more overseas trucks going through from the east. The defunct Lorry Road User Charge shows that it is very difficult to find a charging system that would work without adding considerably to the tax burden of British hauliers.

Still, the chances of the Liberal Democrats coming to power are small, unless they join another party in coalition.