LONDON - The British government on Tuesday approved construction of a controversial high-speed rail link between the country's two biggest cities, despite opposition from many residents along the proposed route.

The 225-kilometre line, known as High Speed 2, will carry 360 kph trains and shorten journey times between London and Birmingham from almost 90 minutes to 49 minutes. It is projected to cost $50 billion.

Transport Secretary Justine Greening said the project would transfer about 4.5 million journeys per year from air and road to trains.

Some lawmakers, environmentalists and residents oppose the plan, saying the new rail line will ruin tracts of England's picturesque countryside, is too expensive and will not benefit most Britons.

Joe Rukin, who co-ordinated a campaign against the route, said it was "a white elephant of monumental proportions."

"There is no business case, no environmental case and there is no money to pay for it," he said.

But business groups welcomed the investment in Britain's creaky transport network.

"Britain cannot continue to 'make do and mend' when it comes to its substandard infrastructure," said John Longworth, director-general of the British Chambers of Commerce. "Fundamentally, our global competitiveness is at stake."

The Department for Transport said Tuesday that legislation for the new rail line would be introduced next year. It is due to be completed by 2026, with an extension built to more northern cities by 2033.

To appease critics, 13 kilometres of tunnels will be added to the route to spare the countryside.