The attraction for financing companies to become involved in the London Underground PPP is preceisely because of the lack of financial risk. This is one of those projects that has so much impact on the UK economy that it cannot be allowed to fail. Quite simply, if it did, London would grind to a halt. There is therefore always the expectation that in extremis the government would bail out a failing company. With that virtual guarantee of no loss (contrary to the philosphy behind PPP!), there is every likelihood that the whole project will be highly profitable. Even if the company failed, there again would likely be a restructuring of debt with little or no loss to the financiers. Ironically it is this lack of risk that makes it likely the PPP will have to be declared as quasi-public borrowing and therefore included in the goverments public borrowing figure rather than being "off the books". As the whole intention of the PPP process is to move borrowing for public investment off the Government's books  and either onto the private borrowing figures or into an accounting "black hole", the PPP process is a failure for the Government.

Ken Livingstone proposed the sale of "London Bonds" to pay for the upgrading of the tubes lines which would be paid back over the lifetime of the project. These were rejected because they did not have this golden "off books" status that the PPP then had. You will remember that Gordon Brown has recently been ticked off by the Commission for failing to meet the Convergence Criteria because of government borrowing. This was a result partly of him being forced to re-assign some PPP borrowing back to the PSBR (public sector borrowing requirement) by the National Audit Office.