HS2 Rail Link 'Will Boost Economy By £15bn'
The Transport Secretary has indicated changes could be made to the £42.6bn HS2 project as the Government launched a fightback over its plans.
Patrick McLoughlin admitted the high-speed rail scheme was not perfect and promised to "adapt and improve" it in light of recent criticism.
He also conceded there was "scepticism" about ministers' promises on big projects but insisted the project was "on course, under control and on the budget I set".
New analysis by accountants KPMG concludes HS2 will be worth £15bn a year by 2037 in increased tax revenues and productivity gains.
It suggests the boost to regional economies will be equal to between 2.1% and 4.2% of local GDP in Birmingham, 0.8% to 1.7% in Manchester, 1.6% for Leeds and 0.5% for Greater London.
Mr McLoughlin vowed to "squeeze every penny" of economic benefit out of the project in a keynote speech in Westminster.
The address forms part of a campaign announced by David Cameron to make the case for HS2 in the face of what he called an "unholy alliance" of sceptics.
It came after MPs on the Commons spending watchdog warned in a scathing report that its apparent benefits were dwindling as the costs spiralled.
The Public Accounts Committee said the case for the massive project was based on "fragile numbers, out-of-date data and assumptions that do not reflect real life".
Other recent critics have included Labour's Alistair Darling who first approved it as chancellor, and the Institute of Directors which dismissed it as "a grand folly".
It is also fiercely opposed by some Tory MPs - many representing communities which will be disrupted by construction work and train noise along the route.
Mr McLoughlin said: "The last few weeks have seen old criticisms return in new guises. About cost. About capacity. About the balance between North and South.
"And I don't dismiss all such criticism. Some of it is well-meant. Some of it is well-informed. Some of it is ill-informed and deliberately misleading.
"All of it deserves - at the very least - to be listened to respectfully so where we can adapt and improve our plans my promise is that we will.
"The new north-south railway is a project that will last over decades and no doubt over several governments too. We are still consulting. Parliament will have its say."
He added: "It would be absurd to claim we have got every bit right, that not a single thing can be improved."
However, he insisted it would be pointless "patching up" existing infrastructure and that extra capacity was needed to give a "heart bypass" to the "clogged arteries" of the existing network.
HS2 would free up existing lines for shorter commuter and freight services, he argued, potentially saving half a million lorry journeys on the motorways.
"We will squeeze every penny of economic advantage out of HS2 and Britain will be richer because of it," he said.