Devolution is more important than Brexit and could be the issue that divides "traditional party tribalism", according to the former Treasury Minister who helped develop the Northern Powerhouse concept.
Economist Lord Jim O'Neill told the audience at the Great Northern Conference in Leeds today that MPs who ignore the "clear desire and ambition" for powers and resources to be handed from central government to local leaders could face severe consequences.
He spoke as Northern Powerhouse Minister Jake Berry claimed it was time for local leaders in Yorkshire to "rise to the challenge" of agreeing a new devolution agreement following the Government's rejection of the One Yorkshire plan earlier this month.
Ahead of a meeting between One Yorkshire supporters and Communities Secretary James Brokenshire on Friday, he said the road to devolution in Yorkshire "is now clear" but stopped short of outlining any specific proposals.
And Judith Blake, the leader of Leeds City Council, said the region's political leaders were ready to "move forward in the spirit of collaboration".
Delivering the keynote speech, Mr Berry said remained a centralised country but that metro mayors in the North had "helped change the balance of power between Whitehall and town hall".
He said: "Most recently in Yorkshire, we wrote to local leaders, setting out our ambition to commence discussions about devolution, Hull and the Humber Estuary, Leeds City Region, York and North Yorkshire.
"So what I would say is, the road to devolution in Yorkshire is now clear, but it is time for local leaders to rise to that challenge.
"The reason that is important is that if we can agree the deals for devolution in the rest of Yorkshire, it will mean that 75 per cent of people in the North of England will have the benefit of devolution.
"Devolution matters because it is how we empower communities, it is how we put the levers of economic growth in the hands of local leaders."
Prior to the One Yorkshire concept of a region-wide mayoral authority being developed, plans for a Leeds City Region deal hit the buffers due to opposition from Yorkshire Conservatives.
Lord O'Neill, who is vice-chair of George Osborne's Northern Powerhouse Partnership, said the Government had correctly ruled out a Yorkshire-wide deal on the basis of economics.
He said: "I encourage fresh serious focus on four urban-based deals for all of the Yorkshire county to be resurrected.
"We have seen Brexit in the past week finally dividing traditional party tribalism, devolution should do the same, because it is more important than Brexit itself.
"I think that MPs that want to ignore this kind of clear desire and ambition for more local focus in life, the consequences will be the same, in fact perhaps even, ultimately, more severe."
In his speech, Archbishop of York Dr John Sentamu said the One Yorkshire deal meant "strong cities, towns and villages not pitted against one another but pulling in the same direction for the betterment of the many".
He said: "The One Yorkshire plan has received cross-party support and backing from the CBI, the Federation of Small Businesses, the Institute of Directors and the TUC. Not because of who they know, but because of what they can see.
"And, of course, as an adopted Yorkshireman my instinct is to demand of Ministers: what are you afraid of?
"But this isn’t a conflict. This isn’t a war. There is enough on the plates of those we have elected to serve us, and so we must work harder and smarter to make our case compelling enough for them to enable our vision and let us realise our ambitions.
"Our true potential, unlocked right across the North of this great country."