Engineers have warned that a planned high speed rail network with Birmingham at its heart must not repeat the mistakes of Britain’s first high speed railway line, which connects London and the Channel Tunnel.

The warning came from the Institution of Engineering and Technology as the National Audit Office published a report concluding that passenger numbers on the Channel Tunnel line, known as High Speed One or HS1, are falling far short of original forecasts.

The project costs of the £6.16 billion London to Folkestone line have exceeded the value of journey-time saving benefits, the National Audit Office report said. And passenger numbers between 2007 and 2011 were only two thirds of the level forecast.

Chris Richards, transport policy advisor at the Institution of Engineering and Technology said the report illustrated the need to ensure the new rail line, known as High Speed Two, had a business case that stood up to analysis.

He said: “This report highlights the need to get the details on High Speed 2 right from the outset. In our response to the Department for Transport consultation we made it clear that there were potential flaws in the analysis, several assumptions were made in crucial areas and serious questions have been left unanswered.

"The report backs up our concerns as the original High Speed One business case was based on journey time saving benefits and increased rail capacity.”

A report from HS2 Ltd, the business set up to oversee the scheme, will be received by the Government by the end of this month, Transport Secretary Justine Greening said.

To minimise the risk of blight, Ms Greening said she would publish the advice at the same time as naming the sites where the Government planned to build stations.