Failing to build High Speed Rail 2 (HS2) would constitute a "reckless disregard" for the interests of the nation according to Lord Adonis, chair of the National Infrastructure Commission.
Lord Adonis told peers that while challenges lay ahead for the £55.7bn HS2 project, it would "change the country for the better" and argued it could not come soon enough.
The project has caused nationwide division about whether or not it should go ahead. A group of MP’s recently called for changes to HS2’s routes and construction plans to alleviate some of the adverse impacts on residents who live near areas affected by the project.
Lord Adonis, who was a former Labour transport secretary, made his stance towards the project clear while speaking during the Lords debate on the second reading of the High Speed Rail (London-West Midlands) Bill.
The 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 have been raised by former deputy Prime Minister John Prescott, who feared rising costs could see the line stop at Birmingham and not benefit the North.
The case for HS2 has "withstood fierce debate and cross-examination", Adonis claimed.
"From the outset the central argument for HS2 has been about capacity with speed and connectivity significant additional benefits,” he said.
"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."
"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 Adonis, who pointed out the last improvements to the West Coast mainline had cost £9bn, £1bn of which was compensation to train operators for disruption.
HS2 announced the shortlist of companies that will contribute to the railway’s construction last month with the final contract signings expected to take in 2017 with work starting on site one year later.