The HS2 high-speed rail project is "essential" for the UK's future and the potential gains "significantly outweigh" any risks, MPs have said.

The Commons Transport Committee also said the estimated cost of up to £50bn had been exaggerated, leading opponents to think ministers were offering a "blank cheque".

And extending the link to the north of England should be speeded up, it added.

But the Stop HS2 group called the report "a cheerleading whitewash".

Tunnelling

HS2 would cut journey times between London, the Midlands and the north of England.

The first phase, from London to Birmingham, is due for completion in 2026, with a second Y-shaped section from Birmingham to Manchester and Leeds due to be finished in 2032-33.

The committee said serious thought should be given to building the two phases at the same time.

It said incoming HS2 Ltd chairman Sir David Higgins should report to ministers by the end of next year "on options for speeding up HS2 so that trains run north of Birmingham on high-speed routes well before 2032-33".

The cost of the project in its entirety is estimated at £42.6bn, with £7.5bn needed for the high-speed trains. Of the £42.6bn, a total of £14.56bn is contingency.

The committee said: "The Department for Transport's (DfT's) communications about HS2 should emphasise that the estimated cost is £28bn, not £50bn, and that cost increases to date have largely been due to the decision to undertake more tunnelling and other work to mitigate the impact of the project on people living near the route."

'Limitations'

But its support for HS2 "was not unqualified", the committee added, saying it remained concerned about how Heathrow would be incorporated into phase one and what impact including a stop at the airport would have on the budget.

Joe Rukin, campaign manager for the Stop HS2 group, said: "It was clear that this inquiry was going to be a cheerleading whitewash when the transport committee only called people who support HS2 to give evidence.

"Despite the official cost of HS2 standing at £50bn, the committee want to pretend it is £28bn, even though they said it would be £34bn in 2011.

"In saying this and telling the DfT they should abandon their standard assessments to improve the case for HS2, they are effectively ordering the government to 'spin harder' on HS2."

Dot Whittaker lives in West Gorton in Manchester and has been told her home is one of 40 that needs to be demolished to make way for the line.

"It's going to cut about half an hour off a journey," she told BBC Radio 5 Live. "At what cost?

"We already live on top of the existing line that runs into Piccadilly and now we're being told that we've got to make way for another one, and it's absolutely horrendous."

But Transport Secretary Patrick McLoughlin said HS2 would be a "heart bypass for the clogged arteries of our transport system".

"We therefore welcome the Transport Committee's conclusion that the new North-South railway is the best long-term solution to increasing capacity and that alternative proposals would simply not cope with the predicted increase in demand."

On BBC Radio 4's Today programme, committee chair Louise Ellman recognised the importance of continued investment in existing lines, but added: "It's very clear that HS2 is the only way that much-needed capacity on railways can be produced and it will also bring better connectivity between the country."

Labour's Mary Creagh said her party supported HS2 "because we must address the capacity problems that mean thousands of commuters face cramped, miserable journeys into Birmingham, Manchester, Leeds and London", but she criticised the government for allowing costs to "balloon".