Boris Johnson should “manage expectations” on how long it will take to complete his plan to “level up” left behind communities across the UK, a Tory MP has said.

Kevin Hollinrake, who is Michael Gove’s parliamentary private secretary, said the economic gap between the north and the south-east was comparable to the disparity between East and West Germany before reunification.

He told HuffPost UK’s Commons People podcast that, as in Germany, it would take 30 years to complete the levelling up agenda, which was front and centre in the Queen’s Speech this week but is still posing questions about how the prime minister sees it progressing and how its success can be measured.

Hollinrake suggested that average wages in different regions could be a reasonable measure of the success of levelling up, but warned that it was “dangerous measuring outcomes rather than opportunities”.

The Thirsk and Malton MP also stressed that levelling up was a “huge task” that could take decades to be completed.

He told Commons People: “Levelling up is really exciting, it’s a big ambition, it’s a huge task.

“The economy disparity between London and the south-east and the north-east in relative terms is as big as it was between East and West Germany prior to reunification – two-and-a-half times – a phenomenally big gap.

“So this is going to take three decades to resolve it, that’s what it took Germany and they haven’t narrowed it completely yet.

“It’s going to take three decades and – two trillion dollars Germany spent on narrowing that gap, we’ve got to be in it for the long haul.”

Hollinrake went on: “I think it’s important to manage expectations, that this isn’t going to happen overnight.

“There are some things you can do really quickly – so yes building a road, a railway or a railway station takes a while to have an economic effect.

“But other things can happen more quickly, such as relocation of civil service jobs – Treasury north coming to Darlington, Cabinet Office going to Glasgow, Michael Gove was there this week, you’ve got the UK Investment Bank coming to Leeds.

“So things can happen pretty quickly and that’s all there now, or just about being put in place now.

“Freeports as well, these tax-free zones will attract a lot of private sector investment.”

One of the quickest ways to deliver on levelling up would be reform of the tax system, Hollinrake suggested.

“There’s some things in-built in the tax system that aren’t particularly fair, council tax is one of them for example. There’s a proportionately higher burden on parts of the country,” he said.

“Very expensive properties in London for example pay a fraction of the council tax we pay in a much smaller house in the north, it just can’t be fair.

“There’s ways you can do things like that, I’m not going to pre-empt what the chancellor might do.

“Business rates I think again are due for reform.

“There are lots of different things we could do to make it a fair and more level playing field, which would then encourage investment in different parts of the country.”

Hollinrake suggested there may be value in measuring the success of levelling up by looking at average wages across regions.

But he stressed that ultimately the agenda’s success should be judged by how much it creates equality of opportunity across regions.

Asked how the success of levelling up should be measured, he said: “Average wages, for example, would be a good measure that we should use.

“But it’s very dangerous measuring outcomes rather than opportunities because clearly not everybody makes the best of their opportunities and it’s got to be about the individual as well as the state.

“In fact, it’s much more about the individual than the state.

“For me, you create a fair and level playing field, a stable framework that encourages investment, and things like infrastructure are really important to do that as well as the tax breaks, and then let people get on with it.”