It’s been a long time coming for Crossrail 2. The Hertfordshire-to-Surrey line received government backing this week after years of dashed hopes and false starts.

Chris Grayling, the Transport Secretary, confirmed on Monday the government’s commitment to the £30 billion project. The exact funding deal will be thrashed out with the GLA over the coming months. But for a scheme that has been left out in the cold for so long – and was notably missing from the Conservative manifesto and Queen’s Speech – the announcement is a huge leap forward.

Crossrail 2 will seek to tackle overcrowding by tunnelling beneath the Capital to connect Wimbledon and Tottenham Hale, and link the suburbs beyond. It will also provide a vital connection to the HS2 terminus at Euston.

The news has been received with much fanfare in London. However, others have pointed out that infrastructure investment should not be a zero-sum game. The electrification of trains in Wales, the Midlands and the North, for example, should not be derailed to make way for additional investment in London. Manchester Mayor Andy Burnham said Northern commuters would be angry at the news, while Liverpool’s Steve Rotheram said there should be balanced spending across the UK.

The two metro mayors certainly have a point. Transport expenditure is currently around £2,600 per head in London compared to only £99.19 in the North West and a measly £5.01 in the North East. As the clock ticks down on Brexit, the government should think carefully about how to raise confidence in the UK economy. What better way than to share investment across our great cities, not just London?

It is equally important that Crossrail 2 is not seen narrowly as a transport project. London’s railways have long been a catalyst for growth: The leafy suburbs of Metroland, which are still desirable today, were opened up by the arrival of new railways in the early twentieth century.

There are more constraints nowadays: the Green Belt restricts development and the Mayor of London is expected to give greater protection to strategic industrial land in his emerging London Plan. This makes it all the more important to maximise densities around key transport nodes.

According to the development industry, Crossrail 2 will enable the delivery of 200,000 new homes and the same number of new jobs. This is all good news, but what’s needed now is a clear plan to deliver this target.

What about re-zoning some Green Belt land around stations in the commuter belt, for example? Is a car park in Hertfordshire really as valuable as new homes next to a flagship transport hub?

Crossrail 2 is still a long way off. Government support is one thing, but we’re going to have a long wait – 2033 with a fair wind – before the line is open for business. In the meantime, we need to think carefully and creatively about how to take full advantage of the new opportunities.