Liverpool, Manchester and Leeds are separated by a mere 65 miles. Yet board a train at one end of this corridor and it will be nearly two hours before you alight at the other end. We ought to be seriously considering building a high speed alternative.

The current Transpennine Express trains trundle across the Pennines with a meandering listlessness reminiscent of a distracted pony. They huff and puff and creak and groan. Calling them "express" trains is an outrage against the English language. Transpennine passengers enjoy glorious scenery, but appalling speeds. As Andrew Adonis has drily noted, it is "quite an achievement" that the 45 mile journey between Leeds and Manchester takes almost an hour. Although the route is set to be electrified, the work will make only a marginal difference to journey times.

Of course, Britain is riddled with slow rail connections and plenty of trains huff and puff, but this case is different. This transport corridor links three of the six largest cities in England. Liverpool is the fastest growing city outside of London and Manchester is increasingly heralded as the UK’s second city. Surely our major cities should be better connected?

This issue is even more pressing in light of the economic importance of bringing businesses closer together - so-called "agglomeration economics". Nowadays, economic growth seems increasingly to be driven by large urban hubs where workers and businesses in close proximity compete, collaborate and copy each other much more intensively than they otherwise would do. Mixing in these ways drives innovation and productivity gains. As Evan Davies explained in his recent documentary Mind The Gap, London benefits from these "economies of distance" in a way that other parts of the country do not – and it is powering Britain’s economic recovery as a result.

Yet Davies also emphasises that the area from Liverpool through Manchester to Leeds is the prime candidate for an extended travel to work zone outside of London. With populations expanding again after decades of decline, these cities have the potential to form a robust corridor of economic activity, a northern hub.

This will depend, however, upon better transport links. As things stand, the area is hobbled by poor rail connections. Research by the LSE found that approximately 40 per cent fewer commuting journeys are made between Leeds and Manchester than would be expected given the cities’ proximity and size. Such statistics will hardly surprise regular Transpennine travellers, but they underline the extent to which poor transport connections are holding back business growth.

The government’s current plans for HS2 do nothing to address this problem of east-west connectivity. In fact, while the government has portrayed HS2 as an economic panacea for the north, the matter is far from clear. Many experts have argued that HS2 is more likely to draw more wealth into London than it is likely to spread it northwards. Unsurprising, then, that northerners show little enthusiasm for HS2 with 22 per cent strongly opposing the scheme in Yorkshire and only 10 per cent strongly in favour.

By contrast, a high-speed rail connection between Liverpool, Manchester and Leeds would be transformative for the north, drawing journey times down toward those of a standard Underground commute and thereby boosting business growth. It would cost far less than HS2 and would be more readily deliverable.

As things stand, however, we are in danger of allowing the controversy swirling around HS2 to stymie further thinking and plans for high speed rail, plans which should be judged on their own merit. Irrespective of whether the case for HS2 adds up, a connection from Liverpool to Leeds ought to at least be on the policy agenda as an option and subject to the careful cost-benefit evaluation of any major infrastructure project. When discussing high speed rail, we ought to be going beyond HS2.

David Kirkby (@kirkbydj) is a researcher at Bright Blue