A SCATHING report has been produced by a committee of MPs into Government claims about the benefits of High Speed 2.

The Public Accounts Committee has branded some of the Department for Transport's assumptions about how the £33bn scheme will help the economy as 'nonsense' and 'untenable'.

A study into the completion and sale of High Speed 1 and what lessons it provides for HS2 makes grim reading for transport chiefs.

Criticism of the first high speed rail scheme centred around the fact taxpayers have so far spent £4.8 billion to cover the debt on the project – and will continue to shell out £10.2 billion over the next 60 years.

The committee concluded that the root of the problem was the “inaccurate and wildly optimistic forecasts for passenger numbers”.

Campaigners have claimed the same inaccurate predictions have been made on HS2.

Committee chair Margaret Hodge said such 'costly mistakes' must not be repeated with HS2.

She said: “Before going ahead with HS2 we need a robust cost benefit analysis.

“Some of the Department's assumptions about the benefits of faster travel are simply untenable.

"For example, the time business travellers save by using high speed rail is valued at £54 per hour yet the time commuters save getting to and from work is only valued at £7 per hour.

"It is difficult to see how this can be justified.

“The Department also assumes that all time spent on a train is unproductive.

"And unrealistic assumptions about ticket prices act to exaggerate passenger demand forecasts.”

The DfT admitted it had ignored investment in broadband video-conferencing and other alternatives, Mrs Hodge said.

“It is nonsense that the Department does not have a full understanding of the wider economic impact and regeneration benefits of transport infrastructure, including HS1, to inform future investment decisions.

“The Department must revisit its assumptions on HS2 and develop a full understanding of the benefits and costs of high speed travel compared to the alternatives."

The true benefit to the taxpayer and economy has come under increasing scrutiny in Parliament recently, with this report being the latest blow.

The DfT stressed in a statement that the report acknowledges HS1 is an important part of the rail infrastructure.

It said: “Our passenger forecast modelling has improved significantly since the original work for HS1 over 20 years ago, with better understanding of what drives passenger demand, better computer modelling and more computer power to do it.

“Network Rail predicts the West Coast Main Line will be full by the mid 2020s and HS2 presents the most effective solution to this looming capacity crunch facing our rail network. "This is in addition to the jobs, regional regeneration and improved connectivity the project will deliver.”