The controversial High Speed 2 (HS2) project needs a ‘rethinking’, according to a group of peers who fear the northern section of the £55.7 billion line will not benefit passengers.

The House of Lords’ Economic Affairs Committee claims the government has made “little progress” in answering questions it raised in a 2015 inquiry.

At the time, the committee said there was a strong case for prioritising Northern Powerhouse Rail – a programme of infrastructure improvements to the network in the north – but that the government had “failed to consider” whether the scheme was a better investment than HS2.

In the latest report, the committee recommends combining the second phase of HS2 development – the northern section of the line – with Northern Powerhouse Rail. It claims doing so would allow for investment to be prioritised “Where it is most needed”. The committee is also calling for funding for the northern infrastructure project to be ringfenced and brought forward.

The Lords also raised concerns that HS2’s costs are “out of control”. Former chairman of the project and Crossrail reportedly told the committee that “nobody knows” what the final cost of the scheme will be. The worries echo fears raised by the Taxpayers’ Alliance in 2017, which claimed the bill for the project could hit £90 billion.

The committee says it worries that if spending on phase one – the London-Birmingham link – overrun, the northern sections “may not be built”.

“An appraisal method that took more account of the transformative benefits of new infrastructure would be less sensitive to small changes in journey time,” according to the report.

In addition, the committee says the government should consider whether lowering the speed of the trains once they are operational would provide cost savings. HS2 trains will travel at 360 kilometres per hour – faster than any other train in the world, according to the report.

The report also raised another point from the 2015 inquiry, which called for HS2 to terminate at Old Oak Common to connect to central London via Crossrail rather than Euston, which will “require expensive tunnelling”. The committee is calling for the redevelopment of Euston station to be removed from the scope of the first phase and for the government to determine whether Old Oak Common would be a better ending point.

Lord Forsyth of Drumlean, chairman of the Economic Affairs Committee, said: “Commuter services in the north of England are badly overcrowded and reliant on ageing trains. Rail connections between northern cities are poor. As the Committee suggested in its 2015 report, rail infrastructure in the north should be the government’s priority for investment, rather than improving north-south links which are already good. The north is being short-changed by the government’s present plans, especially as construction on HS2 is starting in the south. Any overcrowding relief from HS2 will mainly benefit London commuters.

“The costs of HS2 do not appear to be under control. It is surprising therefore that the government has not carried out a proper assessment of proposals to reduce the cost of HS2 — such as lowering the speed of the railway or terminating in west London rather than Euston — which the committee recommended in 2015. A new appraisal of the project is required.”

Read the committee’s full report here