Dramatic cuts in journey times between Birmingham and the North will "transform" the economy of the Midlands, a major new Government study claimed.

Sir David Higgins, chairman of the planned new high speed rail line, said the new network would help the rest of the country achieve the same economic success as London.

He confirmed plans to extend the high speed line from Birmingham in two directions, to Manchester and Leeds, as well as to build an extension across the Pennines – known as HS3 –to link the North East and North West.

And in a new report, he set out a reduction in journey times between Birmingham and destinations in the North of England which the new line will achieve.

The proposals are the latest stage in the Government's plan to create a "Northern Powerhouse", bringing together cities such as Manchester, Liverpool, Leeds, Sheffield and Newcastle into a single economic area, largely through the dramatic improvement of transport links.

David Cameron and Chancellor George Osborne, who is overseeing the Northern Powerhouse policy, used the launch of Sir David's report to announce the creation of a new transport authority called Transport for the North.

This will oversee the implementation of a range of transport infrastructure schemes.

The Chancellor is set to announce funding – of up to £15 billion – in his Autumn statement, due on December 3. But Sir David, chairman of HS2, insisted the measures would benefit the Midlands too.

He said: "The journey time, for instance, between Birmingham and Leeds, the centres of Britain's largest two manufacturing regions, would shrink from 118 minutes to just 57.

"The effect should be transformational. The result should be not a zero sum game in which London loses out to the Midlands and the North, but a situation in which London grows sustainably, and the Midlands and the North achieve their full potential. The country's productivity will rise as a whole."

The planned HS2 line will cut journey times to Nottingham from one hour 13 minutes to 36 minutes.

Journeys from Birmingham to Leeds will take just under an hour, at 57 minutes, instead of one hour 58 minutes at the moment.

Journey times to York will be cut from two hours 10 minutes to one hour and three minutes, and times to Newcastle will be cut from three hours 14 minutes to two hours seven minutes. And journeys to Manchester will be cut from one hour 28 minutes to 41 minutes.

Sir Albert Bore, leader of Birmingham City Council and Core Cities transport spokesman, said: "Sir David Higgins' report and his key recommendations are welcomed by Core Cities UK.

"It is also reassuring to see our point of view, that better transport links between core cities will generate jobs and growth and help to rebalance our economy, being reinforced by the Government."