Speculation emerged over the weekend that the long awaited Integrated Rail Plan – which is due to publish tomorrow – will ignore calls to deliver High Speed 2 in full including an eastern route between the Midlands and Leeds (pictured).

It is also rumoured that plans for a new high speed Northern Powerhouse Rail line across the region are to be abandoned in favour of cheaper upgrades to existing routes. The reports have sparked concern among northern leaders.

West Yorkshire Mayor Tracy Brabin said suggestions that the Government “will deliver a watered down version of the essential rail links we need to level up the north are extremely worrying”.

She has sent a letter to Boris Johnson in which she highlights the Prime Minister’s prior stated commitments to improving northern transport, and says: “I hope, therefore, that the Integrated Rail Plan will set out how you intend to deliver HS2’s eastern leg in full, along with Northern Powerhouse Rail including a new line from Leeds, through a stop in central Bradford to Manchester.

“This must be in addition to the existing commitment to upgrade and modernise the current trans Pennine route,” she adds. “The Government has a choice to make. It can choose to unlock the potential of the north, or it can let us down once again.”

Leeds City Council leader James Lewis also responded to the rumours of a scaled back rail plan for the north and said: “We believe that anything less than a commitment to the eastern leg of HS2 as part of an integrated network with Northern Powerhouse Rail in full would undermine any pledge to ‘level up’ our regions – at a time when we need it most.

“Boris Johnson said on becoming Prime Minister that Northern Powerhouse Rail would do to the north what Crossrail is going to do for London. Crossrail is almost built so cutting NPR now would just reinforce the old north-south divide.”

Northern Powerhouse Partnership director Henri Murison told BBC Radio 5 Live on Monday: “If you don’t have the full HS2 network, if you cut Bradford off and don’t build a new line across the Pennines as is now potentially expected to be announced on Thursday, you have got to ask really serious questions about how on earth we are going to drive up productivity in the north of England.”

He added: “The Oakervee review said we needed to have HS2 and Northern Powerhouse Rail; it wasn’t either/or. But the potential offer to the north this week is neither.”

Former Transport Secretary Lord Adonis of Labour said cancelling the eastern portion of High Speed 2 would be “a historic mistake” that “undermines the whole integrity of the HS2 plan I set out in 2010 after a huge exercise in national planning, to transform the connectivity between the south, Midlands and north in England”.

Speculation over the details of the Integrated Rail Plan comes after a study last week claimed to have found that Bradford – which has been campaigning for a station on the proposed Northern Powerhouse Rail network – currently has the worst rail connections of any major British city.

(Photograph: Network Rail)