Integrated Rail Plan setting out vision for HS2 and Northern Powerhouse rail won't be published until after local elections due to purdah rules

It means the publication, which was originally expected late last year before being pushed back to March, will now not happen until after the local elections have taken place on May 6.

Northern leaders had been expecting to find out in the IRP how the Eastern leg of the controversial HS2 high speed route through Yorkshire would fit in with schemes like Northern Powerhouse Rail which connects the major cities of the North.

And Henri Murison, director of the Northern Powerhouse Partnership, said the continued uncertainty over the future of high speed rail in the North was "costing the region billions of pounds in potential investment and growth".

It comes as the Department for Transport reveals plans to move hundreds of its civil servants to a new 'northern hub' in Leeds as part of a wider plan to move decision-makers out of London.

And Boris Johnson is unveiling a shake-up of the bus sector which aims to see lower, simpler flat fares in towns and cities, turn-up-and-go services on main routes, and new flexible services to reconnect communities.

The Integrated Rail Plan was commissioned last February when the Prime Minister announced that HS2 would go ahead despite concerns about its cost.

The review was set up to decide how Phase 2b of the controversial project could best be delivered alongside NPR and projects like the Transpennine Route Upgrade connecting Leeds, Manchester and York.

But it will also look at how best to reduce cost, prompting fears that key infrastructure improvements such as the Leeds leg of HS2 or a high speed rail station in Bradford may be delayed or downgraded.

Transport for the North was told last month to delay submitting its business plan for Northern Powerhouse Rail until after the IRP was published, meaning parts of the document may have to be rewritten.

In the Commons last week, fellow transport Minister Andrew Stephenson told MPs the Government was "committed to bringing the benefits of high-speed rail to the North of England and work on the integrated rail plan is progressing well".

But Mr Heaton-Harris told this newspaper: "I think we're going to be stuck by purdah, to be quite frank. So I don't think we'll hear about it until after the local elections.

"We were really quite hopeful that we'd be able to but realistically, local government elections, purdah starts essentially in a week's time and there are still elements of work to be done on it so the honest answer is that it's going to be after purdah."

The purdah period occurs before elections and is designed to stop public resources being used for party political reasons during campaigns.

Ministers are expected to "observe discretion in announcing initiatives that are new or of a long-term character in their capacity as a Minister".

Mr Murison said: “Last February the Prime Minister stood up in the House of Commons and promised to deliver HS2 in full, with a plan to be published by the end of 2020 about how it would best integrate with Northern Powerhouse Rail and much-needed upgrades to the current network across the Pennines.

“Yet now the Integrated Rail Plan is further delayed, and there is still considerable doubt not only about the Eastern leg of HS2 but also the new line between Leeds and Manchester via Bradford city centre.

“Without this vital connectivity, the ambition of creating a Northern Powerhouse capable of raising productivity and creating jobs and opportunities for young people is nothing more than a pipe dream.

"As we approach elections, this will be an issue for all of the candidates for West Yorkshire Mayor. When the Cabinet and Shadow Cabinet start campaigning, they will need to be crystal clear on commitments for what the IRP will deliver for Yorkshire.”