1. No it's not, because it's a question of degree and basic service provision - i.e. increased traffic load, and the potential to make fares more affordable - vs decreased travel time and (very likely) even higher fares.

2. Yes, that's the claim. But it relies on intelligent management accepting that telecommuting is an option, not just setting up the infrastructure. Korea's economy isn't comparable because there's far more physical industry there, so there's still a need to shunt people and stuff around in a way that isn't so necessary here. Around three quarters of UK GDP comes from the service sector.

3. It's not clear yet that spending on HST2 will do anything to change long-distance traffic patterns on the corridor either. Rail in the UK is too damn expensive for non-business commuting, and it continues to be cheaper to drive almost everywhere. Unless I've missed something, HST2 is planing to cut travel times, not travel costs.

4. Nice bit of evangelical rhetoric. Not sure how it's relevant to a reality-based economic case though.

And here's another view:

In short, the costs and benefits of HS2 are large and uncertain. I prefer instead to focus on the opportunity costs: are there things that we could be doing with £30 billion that would yield a higher return than `£47 billion'? I think the answer is almost certainly yes, in both the area of transport - more intra-city schemes, for example - and more widely.

On the basis of narrow cost-benefit analysis, this conclusion is backed up by the Eddington report, published in 2006. Comparing the figures for HS2 with those for projects that the Department for Transport had on its books at the time of Eddington suggests that HS2 is, at best, in the bottom quartile in terms of returns (and indeed, might be closer to being in the bottom 10%).

One could say that this is irrelevant because HS2 has a critical mass that will deliver wider benefits. But as I have argued, there is a little evidence to support this assertion. If critical mass is important, then we could consider concentrating a large amount of investment in particular cities - for example, Birmingham, London, Manchester and Newcastle. To the best of my knowledge, no one has assessed what such a package would look like in terms of the wider impacts.

One final objection to my negative conclusion might be that `we have to have HS2 because of capacity constraints on the west coast mainline'. Unfortunately, as the Eddington report showed, by the time HS2 is completed, there will be a great deal of congestion all over the transport network. Other schemes to tackle that congestion are likely to deliver much better returns because these aspects are well captured by traditional cost-benefit analysis and, as I have indicated, HS2 does pretty badly on that.