David Cameron has insisted high-speed rail links to the north of England will go ahead despite a growing backlash at the plans.
The second phase of the Government's plans will take the route beyond Birmingham, with five new stations at Manchester, Manchester Airport, Toton in the East Midlands, Sheffield and in Leeds.
Transport Secretary Patrick McLoughlin is bringing forward public consultation on the plans to 2013 in a bid to fast-track the project.
The £32.7bn plan is one of the coalition's priorities as it tries to kickstart the economy. Construction is due to start in 2017 with the first trains in service by 2026.
Pro-HS2 campaigners hailed the plan as "visionary" but there was immediate concern about the effect on the counties involved.
Some Conservative backbenchers attacked the proposals and the Stop HS2 group challenged claims that it will help the economies of northern cities.
Pressed on whether he could be forced into a U-turn, Mr Cameron said: "This is going to happen. I have been a strong supporter right from the start.
"We do need to rebalance the economy, it has been too dominated by the south and by certain industries and high speed rail will really help to create a better balanced economy."
Chancellor George Osborne insisted the network would be an "engine for growth" in the north and the Midlands, creating tens of thousands of jobs.
He admitted communities along the route would face "very difficult" disruption to their lives but said the economic benefits were "pretty compelling".
The original link connects London to Birmingham, after which it splits into a Y-shape with two branches, one up to Manchester and another to Leeds.
The branch running via Manchester Airport will include a spur to Crewe to speed up trips to Liverpool and Scotland by better connecting to conventional services.
The second branch - which includes Sheffield being served by a station at the Meadowhall shopping centre instead of the city centre - could prove more controversial.
Officials said interconnections would be improved at any stations sited outside cities.
A "parkway" station is set be included at Toton between Nottingham and Derby.
But a proposed spur to Heathrow has been put on hold pending the results of Sir Howard Davies' review of future airport capacity - which is not due to give a final report until the summer of 2015.
Instead, passengers heading to the world's busiest airport will have to change onto the new London east-west Crossrail service for an 11-minute transfer to terminals.
The Department for Transport said the journey from Manchester to Birmingham would be reduced to 41 minutes and from Manchester to London to 1 hour 8 minutes - almost half the present times.
Leeds will be 57 minutes away from Birmingham compared to 1 hour 58 mins today, and 1hr 22mins away from London Euston, down from 2hrs 12 minutes - official projections say.
Mr McLoughlin hailed the rail project as a "once-in-a-lifetime opportunity to transform Britain's connectivity, capacity and competitiveness".
He admitted: "I know that this project is controversial" but added: "This is not about short-term popularity. It is about doing what is right for the country in the long-term."
The project has been welcomed by civic and business leaders in the region, who predict that the number of jobs created could be far higher than the 100,000 cited by the DfT.
But it has also proved controversial, especially in picturesque Tory heartlands which will be affected, such as the Chilterns, infuriating MPs and countryside campaigners.
Conservatives in Chancellor George Osborne's Tatton constituency have already indicated that they will object to plans to route the line through parts of the Cheshire countryside.
Meanwhile, Deputy Prime Minister Nick Clegg, who is also MP for Sheffield Hallam, was forced to defend the move not to run the new line into Sheffield city centre.
"The city centre option is not a cost-free one. It would be a lot more expensive and also the train link would be slower, which slightly defeats the purpose of the whole exercise," he said.
Campaign group Stop HS2 claimed high speed rail projects elsewhere had "sucked jobs to the capital cities" and that this project would do little to regenerate the north.
Chair Penny Gaines said: "HS2 is a London-centric proposal that seems focused on extending the London commuter belt beyond Birmingham, when we need to create an engine for growth in the North, providing access to jobs for people who want to live and work in the North."
Labour backs HS2 - which was begun under its administration - but says there are "worrying signs" that the timetable for delivering it is slipping.
The High Court is currently considering whether the first phase of the project, which will take high-speed trains from London to Birmingham, is legally flawed and needs to be reconsidered.
The challenge was taken to the court by campaigners who accused the Government of failing to undertake a "strategic environmental assessment" or arrange an adequate consultation process.
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