Levelling up has focused too much on 'tarting up town centres' says George Osborne

This includes high speed rail connecting the region from east to west, dubbed The Charles Line, by NRG chairman John Stevenson, as well as reinstating the Leeds leg of HS2.

It comes as the Prime Minister made his expected appearance at the conference, where he appeared to dismiss the NRG’s suggestion of a minister for the north, hours after it had been proposed to the delegates on the conference floor.

“I think [the line] would be completely transformational,” said Mr Osborne.

“It is not enough in my view to upgrade the existing TransPennine line, that’s something we should be doing anyway.

“New infrastructure opens up all sorts of new economic activities that people can’t imagine at the time.

“When the M25 was created, at the time the Treasury was very sceptical. They felt we didn’t need to build it.

“They were against the other big motorways around the country and yet they opened up economic activity that couldn't be imagined in their time.

“I was told to cancel the Elizabeth Line and that’s been transformational in London and we’re seeing the benefits outside.”

He also told critics of HS2 that the project is “nothing but a good thing for the North”.

“It’s not a sponge that will suck activity out of the North or people out of the North, it actually creates that connectivity that is crucial for the economic future.”

Mr Osborne said that the Elizabeth Line, or Crossrail, was first proposed in the mid 1980s and took three or four decades to make progress.

“Once you've got a commitment to these big high speed links, we should go head with them,” he said, adding: “One thing we've learned in this country, is it takes decades for these things to be done, they're very easily cancelled, and when they are cancelled, nothing takes their place.”

He also called on ministers and Tory MPs to take more responsibility over failures to make progress on policy, rather than blaming woke civil servants, or “the blob” of Whitehall.

“Margaret Thatcher, a hero for many of these people, did not go around saying, I'm really would like to privatise the energy companies, or whatever, but I can't, because the blob was stopping me,” he said.

The former chancellor noted that there was a “mistaken focus on quick wins”.

He said that this was the idea of “let’s tart up the town centre” or “let’s plant some new flowers on the roundabout in the middle of the town”.

“I’m not against those things but they don’t make that big a difference.”

Mr Osborne also called on ministers to give mayors a share of income tax which they can reinvest locally, and called on the party to view mayoral seats in Yorkshire as a viable pathway back to power.

"I think it's a very naturally conservative idea that if you give people more responsibility for local decisions, not just how money is spent, but also how it is raised.

“I think the Conservatives should sort of throw the dice a bit politically, and come up with supreme radical ideas around fiscal devolution, giving local areas more powers to set tax rates and keep the money that's raised in taxation.

“There's no part of the country, there’s no part of the North where I can't see the Conservatives winning a mayoralty,” he said.

“This idea that there are no-go areas for the Tories, it’s something the last few years of politics has dispelled.

“When I was elected they would have said it was impossible to win Don Valley. It used to be a reason why Conservatives were against both creating these large metro mayors and giving them more powers. I think those reasons have gone away because in Teesside and the West Midlands we’ve proved we can win.”