Its ‘Rethinking High Speed 2’ report suggests that cost cutting measures should be explored including lowering the speed of the railway or moving the London terminus to Old Oak Common, rather than Euston.

“The costs of HS2 do not appear to be under control,” said committee chair Lord Forsyth of Drumlean. “If costs overrun on the first phase of the project, there could be insufficient funding for the rest of the new railway.

“The northern sections of High Speed 2 must not be sacrificed to make up for overspending on the railway’s southern sections,” he added.

The report calls for a new appraisal of the business case for High Speed 2 by the end of the year, taking more into account its ‘transformative’ benefits rather than focusing so much on journey times.

A further recommendation is that the northern leg of High Speed 2 to Manchester and Leeds should be combined with plans for Northern Powerhouse Rail, and treated as one programme.

“The north is being short changed by the Government’s present plans, especially as construction on HS2 is starting in the south,” said Lord Forsyth, who urged rail infrastructure in the north to be the Government’s priority for investment.

However sub national transport body Midlands Connect said the report recommends major changes to High Speed 2 ‘without any consideration of the transport needs and opportunities in the Midlands’. It opposes proposals to lower train speeds or move the project’s London terminus.

Midlands Connect chairman Sir John Peace added that phases one and two of High Speed 2, combined with the Midlands Rail Hub and Northern Powerhouse Rail are all needed as soon as possible. “If we start favouring one over the other, we risk delaying them all and undermining our economy at a time when we need to be working together more, not less.”

Also responding to the report, a Department for Transport spokesman said: “The report is a thorough assessment of a complex project, however we fundamentally disagree with parts of it.

“By 2020, the Government will have invested a record £13Bn in transport across the north, and we have a clear plan for linking the Midlands and the north through HS2 and Northern Powerhouse Rail – the full benefits of which can only be delivered on the back of HS2. This is not either / or, we are clear we want both.”

(Photograph: HS2 / Grimshaw)