Furious political leaders in the north of England have raised fears about the future of the "Northern Powerhouse" after the Government scaled back transport plans for the north while backing billions more for the south.
Transport Secretary Chris Grayling sparked anger by supporting a new £30 billion Crossrail 2 scheme in London and the south-east, days after a series of rail projects in Wales, the Midlands and the north were axed or downgraded.
In a joint statement, leaders in Manchester, Liverpool, Leeds, Sheffield and Newcastle said Mr Grayling's statements had created "considerable uncertainty" and raised fears about the future of the "Northern Powerhouse" and the Government's aim of rebalancing the UK economy.
The statement said: "If the Government can't be trusted to stick to promises already given, then it is hard to have confidence that they will deliver longer-term agreements made to the north.
"The Government urgently needs to clarify its position on both short-term and long-term commitments to the north and confirm if it remains committed to the Northern Powerhouse and Transport for the North."
The political figures, including Greater Manchester Mayor Andy Burnham and Liverpool City Region Mayor Steve Rotheram, said they plan to convene a summit for northern political and business leaders in late August, before the return of Parliament.
The statement said: "We call on the Government to return to working constructively with us to correct long-term imbalances in transport funding and to give the people of the north the rail services they deserve and have been promised."
Manchester City Council leader Sir Richard Leese, Leeds City Council leader Judith Blake, Sheffield City Council leader Julie Dore and Newcastle City Council deputy leader Joyce McCarty also gave their backing to the statement.
The Department for Transport (DfT) has insisted money for the north is not being cut, despite earlier pledges to electrify trans-Pennine rail lines to improve speed and capacity now being shelved.
Instead, new "bi-mode" trains which run on diesel and electricity are planned. Critics say electric trains are faster, cleaner and greener.
One scheme, the electrification of the line between Leeds and Manchester, part of a wider plan to upgrade the entire trans-Pennine line west from Liverpool to Hull and Newcastle, was seen as a key element of the "Northern Powerhouse" to boost the economy across the region through a "Crossrail for the North".
The Institute for Public Policy Research (IPPR) North think tank has launched a petition calling for the Government to fund Crossrail for the North.
Ed Cox, director of IPPR North, said: "Over the past decade we have spent £59 billion more in London than in the north of England so over the next decade there's £59 billion catch-up cash should be devolved to transport for the north."
Crossrail 2 will run across London between Hertfordshire and Surrey at an estimated cost of £30 billion. The new scheme would start in Epsom, Mr Grayling's constituency.
Crossrail 1, already under construction in London, is estimated to cost £14.8 billion and runs through Maidenhead, whose MP is Theresa May.
A DfT spokesperson said the Government was investing more than £1 billion in rail across the north and £800 million on new road schemes in the north-west, and no public money has been committed yet to Crossrail 2.
The spokesman added: "Building transport infrastructure has the potential to drive economic growth, create jobs and spread wealth across the country. That's why we're spending £55.7bn on HS2, which will better connect Manchester and Leeds to the Midlands and London.
"It's also why we're committed to improving trans-Pennine services, and are working with Transport for the North to cut journey times and increase capacity between the major cities of the north.
"We are currently investing over £1 billion to improve rail infrastructure across the North of England, and major upgrades to the Manchester-Leeds-York route are being designed and developed. We are also investing £800 million on new road schemes in the North West, creating around 600 jobs - including upgrading the M62 to a four-lane smart motorway.
"In spending taxpayers' money, it's vital for the Government to deliver value for the whole country. So while we have agreed to work further with Transport for London on Crossrail 2, we have also said that London needs to pay half of the upfront construction costs and we have not committed any public funding yet."