A new deal between Manchester, Liverpool, Dublin and Belfast could help the areas become world leaders in green energy, Andy Burnham has said.

The mayor of Greater Manchester, along with Steve Rotheram, mayor of the Liverpool city region, signed the agreement at the end of a visit to Ireland and Northern Ireland focused on building economic and cultural ties.

The agreement includes commitments to share best practice, knowledge and experience, to facilitate R&D, investment and business collaborations, and to co-ordinate joint participation at events.

Mr Burnham told the PA news agency that the agreement had come at the right time to deal with challenges being faced in energy markets.

He said: “The time has come to pull these four cities closer together and not see the Irish Sea as the thing which divides us but which is actually the source of some of our common solutions.

“Ireland north and south has shaped the North West of England over the centuries. It has made us who we are.

“Steve and I feel the opportunity is there to get much closer.”

The deal was signed at Belfast City Hall with the Lord Mayor of Belfast Kate Nicholl and the Lord Mayor of Dublin Alison Gilliland.

While in Belfast, the four mayors travelled to a number of engagements by hydrogen bus.

Mr Burnham said: “The deal is a starting point. I put forward the idea that the first tangible outcome might be a four city conference in Liverpool or Manchester, particularly focused on this issue of green energy.

“Today in Belfast we have been looking at green hydrogen, particularly as it is generated through wind power, and there is a serious opportunity for us all to grab, which is becoming a leader in that technology.

“From a Northern Ireland and Irish point of view, the need is not so much here that might justify the investment in the infrastructure, but when you are thinking of our part of the world and all the consumers there, then that changes that.

“I don’t see any reason why Ireland north and south, and the North West of England can’t be a world leader in green energy because we have got the geography and the assets that others have not.”

Mr Burnham said there were other reasons for the new partnership.

He added: “The single biggest market for inward tourism in Manchester is Ireland, we have 162,000 visits from the Republic of Ireland.

“Ireland is in the top three when it comes to our trading partners.

“Brexit potentially puts that at risk.

“Steve and I were quite conscious that people in Ireland might think the North West had changed. You hear voices in Westminster purporting to speak for all of us when quite frankly they don’t.

“It is worth coming over here to remind people that the Westminster Government speaks no more for us in the North of England than it does for people in Ireland or Northern Ireland.

“We often feel the same frustration at the way we are treated.”