Boris Johnson will face brutal backlash if he backpedals on promises to Northern voters - Andrew Vine

Boris Johnson’s pledge at the weekend to build a high-speed rail link from Leeds to Manchester wasn’t a launch event for a general election, but it might just as well have been.

Boris Johnson backs 'visionary and exciting' Northern Powerhouse rail projectIt had the tone and style of a key manifesto commitment, was delivered by a Prime Minister casting himself in the role of a man who gets things done, and attempted to kick Labour’s legs from under it.

'We need high-speed rail across the North': Leaders challenge Boris JohnsonThat there will be an election within the next year seems certain, and Mr Johnson has put down a marker that the Tories will give Labour a real fight in the North.

For all of us who live here, it has to be welcome news that the message over antiquated rail services that hold business back and try the patience of the commuters who have no alternative but to use them seems finally to have got through.

Devolution demand to new PMThe case for improving trans-Pennine rail links has been unarguable for years, not just for the sake of the North, but for the benefit of the entire country.

It makes no sense – and never has – to have a vast part of Britain’s economy under-performing because transport links that would be unacceptable in London and the south-east are considered good enough for cities 150 miles north.

A succession of cloth-eared ministers of both Conservative and Labour administrations have failed to listen to the arguments, let alone act on them.

But now Mr Johnson has pledged to make Northern Powerhouse Rail a reality – or at least part of it. It’s possible to quibble over why he didn’t go further and promise better links all the way east to Hull, but what he announced is the best possible start.

We’ve been here before, though, so a note of caution needs to be sounded. It’s five years since the then Chancellor, George Osborne, was making it sound like the Northern Powerhouse was going to get the resources it needs, and it never has.

The North has been consistently let down since then, and whether Mr Johnson realises it or not, that puts him under a great deal of pressure to actually deliver on what he says.

We’ve had enough of broken promises and warm words which never led to adequate funding, and if Mr Johnson attempts to backpedal, it will neither be forgiven nor forgotten.

For now, though, we should take him at his word. He deserves plaudits for heading north as his first engagement outside London and he didn’t have to be cajoled into making the announcement, instead bounding onto the podium full of eagerness to be the bringer of good news.

A measure of how sincere Mr Johnson is in his stated desire to get the North moving will be his response to the One Yorkshire proposals for a county-wide devolution deal unveiled yesterday.

Like the case for a faster rail service, the case in favour of giving Yorkshire the power over its own affairs is beyond argument, and the letter that has landed in Mr Johnson’s overflowing in-tray is both persuasive and chimes with the optimism that has characterised most of what he has said in the whirlwind few days since he took office.

This is a Prime Minister in a hurry, and that could turn out to be a very good thing for Yorkshire.

He needs to make things happen quickly and see results from initiatives to offset possible economic shocks that unfold over the years – or even decades – that follow Brexit.

Boosting the North’s productivity with better transport is an obvious way of doing that, and the eye-catching £30bn economic boost that devolution for Yorkshire by 2022 would bring is an equally easy win.

He potentially wins politically, too, by backing both. The Parliamentary arithmetic he faces when the Commons returns in September is just as forbidding as it was when an exhausted Theresa May left office, and at some point that means going to the country in an attempt to win a workable majority.

That in its turn means winning marginal seats in the North, seeing off the ever-present threat from Labour and taking on the challenges posed by the upcoming Greens and resurgent Lib Dems.

Mr Johnson needs us to like him, so he’s replicating what he did as Mayor of London – throwing money at areas that might not automatically support him to win them over. It worked for him then, and there’s every reason for it to work again.

So there’s as much political expediency in his new-found desire to help the North as there is a genuine wish to address historic inequalities. But we’ll settle for that if it means us getting what we want and deserve. Just so long as he delivers.