There is ongoing debate about the benefits to be expected from the proposed high-speed rail route north from London, known as HS2. The standard transport economic analysis, which recognises the value of time savings from faster travel, yields a very modest benefit-to-cost ratio, even assuming that time spent on trains is completely unproductive. Accordingly, the proponents of HS2 commissioned a different analysis from KPMG which attempts to estimate productivity gains, put at £15bn a year. However, Professor Henry Overman, an expert on this topic, is very critical in two recent blogs (12 and 13 September). He concludes: ‘So, on my reading, [the KPMG report is] technically wrong and possibly out by orders of magnitude.’
It is to be expected that a consultant commissioned by a proponent of a major infrastructure scheme will look for evidence of benefits sufficient to justify going ahead. What is needed is an appraisal of the costs and benefits of HS2 by an impartial body competent to explore the range of valid methodologies.