"The root of the problem is the inaccurate and wildly optimistic forecasts for passenger numbers both when the line was being planned and when the Department for Transport (DfT) restructured its deal with the contractor, London & Continental Railways (LCR)," says PAC chairman Mrs Margaret Hodge. "International passenger numbers have been only a third of LCR's original forecast and two-thirds of DfT's forecast."

Despite this critical assessment, the PAC fails to acknowledge that the complexity of certifying new rolling stock for use in the Channel Tunnel might play a key role in the lacklustre financial performance of HS1. Eighteen years after the tunnel opened, only one high-speed operator and one type of high-speed train is allowed to operate under the Channel. Onerous and outdated safety rules, applied by the Channel Tunnel Intergovernmental Commission, have until now precluded the use of distributed traction trains, while insisting that trains are at least 400m long and capable of splitting in emergencies.

Updating the rules to reflect the safety standards of the latest generation of high-speed trains, almost all of which use distributed traction, has been a long-drawn-out affair made even more arduous by pontificating French ministers and the failure of their British counterparts to take the issue seriously.

Meanwhile operators are lining up to take vacant paths on HS1. Eurostar is eager to expand its network and has ordered Velaro trains from Siemens to serve new destinations. German Rail (DB) also plans to introduce ICE services from London to Cologne, Frankfurt, and Amsterdam, although the launch has slipped back from the 2013 date initially proposed. Both operators will be competing with some of Europe's busiest air routes, bringing in more revenue to HS1 and helping to free up desperately-needed runway capacity at Heathrow and other European airport hubs.

Add to this the Euro Carex plan for high-speed railfreight services, and the growth of European-gauge intermodal freight traffic serving terminals in east London, and the opportunities for greater capacity utilisation are clear.

While there were undoubtedly failures in other areas, it seems absurd that the DfT and LCR should be expected to base their HS1 revenue projections on the persistence of a single-operator scenario. If they had done this from the outset, Eurostar services would still be crawling into London on conventional lines.

The commercial success or failure of HS1 ultimately hinges on the development of a pragmatic safety regime for the tunnel, and the British and French governments need to give the issue more attention if they want to see an appropriate level of return from their investments in high-speed lines and the tunnel itself.

Media coverage of the PAC report will undoubtedly be dominated by opponents of the proposed London – Birmingham high-speed line, who will suggest this report adds weight to the argument that ridership projections for this project have also been overstated. But the two projects exist in very different contexts, and while it would be sensible to review demand modelling, the performance of HS1 to date does nothing to dilute the strong case for expansion of the high-speed network in Britain.