Finally, an HS2 argument from the government that isn’t entirely based on speculative forecasts or political positioning. The transport secretary Patrick McLoughlin has given a speech at the Institution of Civil Engineers this morning, taking on HS2’s growing number of critics.

Of course, it wouldn’t be a transport speech without some economic forecasts. The Department for Transport have released a new report from KPMG, suggesting the line will lead to a £15 billion annual boost to the economy. But the overall theme is about making the HS2 debate about capacity:

‘The reason we need HS2 isn’t for its speed…the benefits of faster journeys are easy to explain. But the main reason we need HS2 is as a heart bypass for the clogged arteries of our transport system..without the capacity provided by HS2 the main road and rail lines linking eight of our 10 largest cities will quite simply be overwhelmed.’

McLoughlin has also taken a leaf from Andrew Adonis on why patching-and-mending the existing West Coast Mainline is not the solution Britain should be striving for:

‘We’ve already spent £9 billion on the last West Coast upgrade but that didn’t finish the job. The overhead wiring is getting on for 50 years old. The bridges and tunnels are Victorian monuments and I’ve been out with the track workers to see them. Pouring billions more in widening it and accelerating it would be like trying to run the M1 up the Old Kent Road.

For good measure, he’s also thrown in some ‘aspiration nation’ rhetoric (of the Boris variety) on why HS2 should be a symbol of modern Britain. Namedropping Brunel and Stephenson, McLoughlin recalls the spirit of these Victorian pioneers and how they relate to the new line:

‘And these lessons from history teach us something important. Big decisions about big infrastructure are always controversial. People have always argued about the unknowns that big infrastructure proposals must always involve.’

‘Much later on people questioned the M25. Or thought we didn’t need the Jubilee line to Canary Wharf whose cost-benefit ratio was even said to be negative. These doubters were wrong.

The transport secretary has wisely acknowledged in this speech the fight is far from over. The anti-HS2 brigade have taken the lead so far, not least because as The Independent has revealed, the head of HS2 Ltd Douglas Oakervee has been forced to take three months leave on health grounds.

But as Benedict Brogan reports in his morning memo, there is apparently no wavering at the heart of the coalition over HS2 and they are ‘determined to make this one stick’. Although George Osborne, David Cameron, Nick Clegg have all publicly supported the project in recent weeks the government still has a great deal to do to win over the doubters.

Tags: Douglas Oakervee, HS2, Patrick McLoughlin, UK politics, West Coast Mainline