Lord Adonis, chairman of the National Infrastructure Commission, told peers that while challenges lay ahead with the £55.7 billion HS2 project, it would “change the country for the better” and argued it could not come soon enough.
The former Labour transport secretary was speaking during the Lords debate on the second reading of the High Speed Rail (London-West Midlands) Bill.
The hybrid Bill authorises the construction and maintenance of the first phase of the London-Midlands-North rail link between the capital and Birmingham and gives the state the power to acquire necessary land to carry out the work.
Concerns were raised by Labour former deputy prime minister Lord Prescott, who feared rising costs could see the line stop at Birmingham and not benefit the North.
But Lord Adonis said the case for HS2 had “withstood fierce debate and cross-examination”.
He said: “From the outset the central argument for HS2 has been about capacity with speed and connectivity significant additional benefits.
“Since 2010 the imperative of more capacity has become greater still, which is essentially why HS2 has withstood scrutiny and controversy.
“It could not be more vital to our economic future.”
He added: “By freeing up substantial capacity on existing lines it also provides a major capacity boost for freight trains and for commuter and regional passenger services into and between the major conurbations of the country.”
Upgrading existing routes was not an option, according to Lord Adonis, who pointed out the last improvements to the West Coast mainline had cost £9 billion, £1 billion of which was compensation to train operators for disruption.
The peer said: “Upgrading a busy mainline railway is like conducting open heart surgery on a moving patient. It’s hardly a compelling alternative to HS2 let alone a cheap one.”
He went on: “One can’t predict the future but we do have to provide for it as best we can.
“In my view it would be a reckless disregard of the national interest on all of the most likely scenarios to fail to provide critical transport capacity between our major conurbations going through to the late and middle part of this century.
“I am not aware of a single country that has introduced high-speed rail between its major cities and now thinks that this was a mistake.
“Of course there are major challenges ahead, not least to keep HS2 to time and to budget, but we are right to be taking HS2 forward. It will change the country for the better and it can’t come soon enough.”
Opening the debate, transport minister Lord Ahmad said: “HS2 is greater than the sum of its parts.
“It’s not just a railway with fast trains. It’s not just about capacity and connectivity. It’s truly about potential.
“It’s about creating opportunities. It is about what is needed to produce a better and brighter future for our country and economy, for connectivity across the UK.
“This is what is required if we are to deliver a better, more integrated Britain.”
Acknowledging concerns about the cost of HS2 and fears it could draw investment from other transport, Lord Ahmad insisted: “HS2 will not come at the expense of the existing transport network.”
He added: “With regards to the costs we are committed to delivering value for money.
“The budget has not gone up. It has simply been updated in line with inflation.
“HS2 is a major commitment of public money but it is an investment which Britain must make.
“We cannot afford not to.”
The minister also highlighted a series of changes made to the scheme to mitigate the impact on the environment and communities, including extending tunnels.
Opposition spokesman Lord Rosser said Labour supported the Bill but pressed the Government for a commitment on phase two of the project, which will connect to Manchester and Leeds.
In the light of the crisis threatening the British steel industry, Lord Rosser also questioned whether the raw material for the major construction project would come from the UK or be imported from abroad.
He added: “We want to see HS2 built. However, there is also a continued responsibility on the Government to listen to the concerns of communities affected about the impact on them of the construction and operation of HS2 and ensuring everything that can reasonably be done to address those concerns is done.”
Lord Prescott: “I hope my contribution is not seen to be negative. It’s a different view. It’s not the Government’s view or the Opposition’s view.
“It’s a northern view - a different perspective of what we are doing with this investment in HS2.”
Highlighting the escalating costs of the scheme, Lord Prescott said: “That’s going to continue for the next 20 years.”
Given the current period of austerity he questioned whether the second part of the project linking to the North would actually happen.
He called for an end to “inequalities” in transport spending and urged investment in northern infrastructure.