I'm writing this while travelling at nearly 200 mph, on a Shinkansen - a Japanese bullet train - from Tokyo to Kyoto.  The journey between the cities will take little over two hours.

We have just one railway line in the country on which such high speed travel is possible - the Channel Tunnel Rail-link.  Yet as the former Transport Secretary, Lord Adonis, has pointed out, typical short-termism delayed that project by decades when the incoming Labour government cancelled the Channel Tunnel in 1974.

That Labour government also cancelled a planned Thames estuary airport at the same time.  It's only too tempting for an opposition party to claim that it is 'saving money' by ditching capital projects.

Lord Adonis said that cancelling HS2, which Labour initiated, would be a "similar act of national self-mutilation".  This didn't stop his former Cabinet colleague, Ed Balls, from casting doubt on the project this week.

It's time to challenge the arguments being made against a high speed rail link to the north.  They say the costs are bound to over-run, but the Olympic project didn't.  They say that existing lines could be upgraded to produce essential new capacity, but this would cost far more than HS2.

They say that the costs would be too great, but a new study by the accountants KPMG has found that HS2 could boost the economy by £15 billion a year.

They say that HS2 will take money away from existing transport investment.  In fact we will be investing more than three times as much as the cost of HS2 on roads, rail and local transport over the same period.

HS2 and local roads improvements aren't alternatives.  Last week the Transport Minister came to Storrington to discuss essential upgrades to the A27 which are, at last, in sight.  But we need to make the case, not just believe fancifully that if HS2 were cancelled an A27 super highway would be the automatic alternative.

As any discussion about housing pressures in West Sussex quickly acknowledges, we need to redress the economic imbalance between the north and the south.  Japan's regional cities thrive by being better connected.  They invested in their bullet trains in 1964.  Now they are planning new, even faster lines.

It's time we caught up.  Britain must cast aside destructive short-termism and invest in the infrastructure a modern economy needs.

Christopher N Howarth