Sir Alastair Morton, the Eurotunnel chief executive, has proposed a tax on transport based on its environmental impact. Emissions, noise, casualties and land-take would be the key components of an index system which would favour modes of transport that caused least harm to non-users. This pollution levy, partly in place of existing taxes, on all forms of transport, would raise L25 billion within five years. This money would go into a transport investment fund, making 50 year loans with low initial interest rates and the fund taking a share of profits.