The Prime Minister announced the decision in the Commons then said before legislation was produced he wanted to see an “integrated plan for rail in the North.”
It would be informed by an assessment by the National Infrastructure Commission and draw on the Oakerview report which recommended HS2 is built in full.
The review would produce “the best way to integrate rail services, including Northern Powerhouse Rail between Leeds and Manchester,” and “the most effective design and sequencing.”
Mr Johnson also announced a minister would work full time on HS2, as well as changes to management to prevent further “blow outs” on cost.
His aim was to see the first services running “by the end of the decade.”
Earlier, political leaders warned the North would not put up with the “scraps” of HS2 while London gets the “gold-plated” stage of the project.
In a joint statement, mayors and council leaders across the North - including Andy Burnham, Steve Rotheram, Dan Jarvis, Sir Richard Leese, Judith Blake, Susan Hinchcliffe and Nick Forbes - welcomed the news that Mr Johnson looked set to back the scheme.
But they also warned any attempt to scale back plans would be a mistake.
They said: “The North of England needs new rail lines that go north-south and west-east. London isn’t being forced to choose, it’s getting Crossrail and HS2; we shouldn’t be forced to either.
“We need HS2 and Northern Powerhouse Rail (NPR) delivered in full. The Government needs to be clear we will not accept a gold-plated high-speed line between London and Birmingham, then once again the North getting the scraps.”
The leaders also responded to talk of bringing HS2 and NPR together under one project.
They added: “We would welcome this to ensure we get the phasing in the right order and that we bring the earliest benefits that we can across the North. If we simply try to bolt NPR on to HS2 infrastructure then we risk repeating the mistakes of the past, where our infrastructure is unable to cope with the growth in demand.
“This would also help us develop the right solution for the vital west-east connections across the North. We need to build the full NPR network – connecting Liverpool, Manchester Airport, Manchester Piccadilly, Bradford City Centre, Leeds, York, Hull, Sheffield and Newcastle.
“After decades of underinvestment in rail infrastructure, HS2 and Northern Powerhouse Rail integrated together represent a once-in-a-generation chance.”