My Lords, when the PPP companies Metronet and Tube Lines collapsed, the Government found themselves having to step up with millions to make up the damage to London Transport because it was essential. It will be exactly the same with Heathrow if there is any failure in the successful completion of this project, and the Government should be honest about that. From doing years of infrastructure funding, I can say that there is no way that any responsible shareholder or lender would put money into a project with so many potential liabilities—for transport, environment, community impact and damage to other airports—without some form of implied government backstop. Will the Government please come clean and provide their estimate of the liabilities that the taxpayer will be exposed to before the vote in the Commons?