The momentum towards delivering devolution in the UK is now “unstoppable”, according to Lord Heseltine, the former deputy prime minister who has been at the forefront of the debate on creating city-based combined authorities with increased powers.

Lord Heseltine’s No Stone Unturned report in 2012, which called for £60 billion of funds to be given directly to regions through a single pot, helped pave the way for the move towards greater devolution and the creation of more combined authorities with increased powers.

He was in Birmingham as moves to create a new combined West Midlands authority come closer to fruition, after Birmingham and the Black Country agreed a historic deal to move forward.

Coventry is also committed to signing-up, with Solihull still considering its options.

It follows the creation of combined authorities this year in the North East, West Yorkshire, Sheffield and Liverpool and the surrounding areas. Greater Manchester has had a combined authority since 2011.

“I think in these last two years we have made more progress than I can remember,” Lord Heseltine told the Post. “The devolution momentum is now unstoppable.”

Lord Heseltine, who delivered a lecture, Changing the role of Whitehall, at the University of Birmingham Business School, said the biggest obstacle to delivering a combined authority in the West Midlands would be persuading those who currently hold power to give some of it up.

And although he did not touch on the subject of an elected mayor for the West Midlands he continues to be a passionate advocate of the idea. Earlier this year he told the Post he was pleased to see elected mayors in Bristol, Liverpool and Leicester.

He said: “Human beings don’t like change and so persuading people with very substantial interests in the status quo there is to be a reallocation of power is a difficult challenge – it is the biggest challenge.”

Describing the process of change as “relatively straightforward to an outsider but complex to insiders”, he added: “You are dealing with a huge range of ambition and machinery, much of which has to change if you are going to achieve a single authority with a single leader.

“To someone arriving here from Mars it would all seem very simple, you just do what every other country does – but not to the people on the ground, whether that is local leaders or Whitehall departments.”

Asked if he felt frustration it had taken so long to get to this point, Lord Heseltine said he remained a realist.

He said: “Of course it would be good if we had more progress years and years ago but I am a Parliamentarian and know that in this country things move at a steady pace.

“That is not a weakness, we are a democracy and you have to take people with you and allow them time to adjust.

“I don’t get over-critical, you are running a country not a business.”

Lord Heseltine also believes Birmingham and the authorities surrounding it are well suited to becoming a combined authority.

Following the recent agreement between Birmingham and the Black Country, a shadow working group will be created to set up the authority.

He said: “I think that any significant economy lends itself to proper management and effective leadership and Birmingham certainly comes in the category of an effective economy.

“It has a huge amount to gain from a single management with an identifiable leadership.

“The way is being led by Manchester at the moment but there are quite a lot of large economic localities that want to catch up and that is a very good thing.

“I myself believe that we need this dynamism across England and across the UK but more specifically England.”

On the issue of London, he believes the capital’s strength can have a beneficial “overspill” effect on the rest of the country, though feels the regions need greater autonomy in order to develop at their own pace and capitalise on their strengths.

“London is now arguably the most successful city in the world,” he said. “It would be deceiving people to say you can get success on that scale in smaller economies but that is not the point.

“Those smaller economies should be given every opportunity to develop as fast as they can and accumulate wealth to the best possible extent within their strengths.”