OK, let's assume all those people previously in favour, in government or otherwise, who have now come or are coming out against it now having had access to the figures, are wrong.
I think ill-informed would be a fairer description - while some would be opposed to HS2 irrespective of the arguments, most people with little background knowledge or interest tend to base their opinion on what they've heard second hand, and that is as true for politicians as anyone else.
Not only does this mean opinions can be influenced by poor reporting, but by stunts like the IEA report whose findings were reported days in advance of the flawed report, ensuring no mainstream critical analysis.
You only have to look to Alistair Darling for evidence of this - according to a a recent radio interview it seems he's under the impression that HS2 and HS1 won't be connected, nor will the line provide an interchange with Heathrow services - he might have been in favour of the project when Labour were in power but he clearly didn't pay much attention to what was actually being proposed.
Let's also assume that all the original projections are correct in that no-one ever does any work on the train nor will do and that every commuted minute is a dead minute as forms a key part of the HS2 calculations.
This is precisely what I mean by people basing their opinion on negative press - if you looked into this whole issue you would quickly see that a) their 'original projections' simply uses the standard analysis that any such project does for calculating the value of saving time and b) it was never actually suggested that people don't work on trains.
It is a generalisation for modelling purposes - while a more sophisticated approach could assume some productive work being undertaken during travel, it would also have to include other factors which also come into play such as the effect of crowding, how the 'saved time' is used, and more besides as discussed in this
strategy unit paper - as it points out...
"Criticism of the current approach tends to focus on whether travellers work on trains, which has led some stakeholders to propose reductions to the value of business time savings in the appraisal of HS2. In isolation, this adjustment would represent an incomplete treatment of the issue.
If the appraisal of HS2 is to allow for the possibility that work may be undertaken during journeys, it is necessary to take into account all of the associated impacts on the appraisal results, including a potential uplift in the
value of de-crowding benefits, and potentially the increased productivity impact of shifting modes. There is considerable uncertainty about how to value these effects."
Chris