The government has finally announced its decision to proceed with a new high speed railway line between London and Birmingham known as HS2. This is a brand new railway line that is designed to run at 250mph/400kph and because of the high speed which means the need for straight sections and avoidance of curves it is especially destructive of the countryside though which it passes. This remains the case in spite of additional tunnelling.

The whole project is characterised by overblown rhetoric about economic growth, reducing the north south divide and making the nation more prosperous. It is of course nothing like this at all. It is a very expensive, very environmentally damaging, very badly thought through transport project. It is one of the most expensive transport projects supported by any government over the last three to four decades and has the weakest justification, business case and rationale.

The project relies on the incredible notion that the time savings for high income passengers translate into huge economic gains and in some mysterious way propagate prosperity and happiness along the viaducts, through the tunnels and along the 75 metres swathe of concrete, overhead wires, access roads and electrical gear that race though Oxfordshire and Warwickshire.

Credibility levels are under more pressure still when it becomes clear that the monetary value of time savings amounts to such a big number because of the assumption that the time spent on these trains is non-productive time. In the parallel universe of high speed rail no one uses lap tops, mobile phones and other technology to get on with work. The forecasts of future demand levels for business travel take no account of the rapid spread of video-conferencing and other technologies that substitute electronic communication for physical travel.

The deeply offensive consultation on HS2 gives the game away. The most important things were not consulted on at all. The massive scale of the environmental damage caused by HS2 is the result of a design that specifies 250mph/400kph running. Faster running requires more engineering and straight lines than a lower design speed. We were not consulted on the route when there are other options that could be used e.g. following motorways. We were not consulted on more fundamental options e.g. if we want to create jobs and reduce greenhouse gas emissions then how does a complete electrification of the UK railways system stack up by comparison?

Supporters of HS2 have linked the project to a low carbon transport future and then revealed the true nature of the project which is simply about encouraging more long distant travel and more carbon emissions. HS2 sits alongside an assumption that long distance car travel will increase 44% by 2033 and air travel by 178% by the same year. The new line will produce an 8% shift away from air and the same away from car. This is just not good enough for such an expensive project and does not deliver climate change or sustainable development objectives.

The starting point for any large transport investment is how it sits within a vision of what kind of society and economy we are trying to shape. The Green Party is very clear on this and we want strong city regions with highly integrated transport systems as good as Zurich or Basle or Frankfurt stretching for at least 50kms around all our major cities. We want excellent inter-city linkages between places like Liverpool,Manchester and Leeds, Liverpool and Glasgow and Exeter, Bristol and Birmingham.

We want excellent rural public transport so that there is a real choice between the car and its alternatives. We want a transport system driven by social justice and fairness and providing high quality choices to all income groups and all localities. HS2 is a rich person's railway and the government knows that spending public money on something that simply will not be used by the bottom 50% of income bands is a reverse Robin Hood strategy. It is a socially regressive project.

At a time of massive cuts in public expenditure and a desperate need to upgrade our big city public transport systems so that they can stand comparison with Frankfurt, Zurich and Vienna the support given by labour, conservative and lib dem politicians to this large scale vanity project is obscene. I challenge all those politicians who support HS2 to go out onto the streets and ask real people to choose between spending £17 billion on reducing the journey time for wealthy rail passengers between London and Birmingham by 23 minutes and all the other things we could do for that pot of money.