LONDON, March 13 (Reuters) – A 400-km per hour British railway will cost 30 billion pounds ($45 billion) to build over more than a decade from 2017, the government said on Thursday, outlining plans to finally get Britain up to speed with Europe.

Britain has only about 110 km of high-speed rail linking London via the Channel Tunnel to mainland Europe, where France, Germany, Spain and Italy all have much bigger, fast networks.

While Japan was the first country to dabble in high-speed railways in the 1960s, both Italy and France had quick trains running by the early 1980s.

''Over the next 20 to 30 years, the UK will require a step-change in transport capacity and connectivity, both to promote and respond to long-term economic growth,'' transport minister Andrew Adonis told parliament.

''High speed rail would be by far the most effective way to achieve this step-change.''

The modernisation, which could accommodate double-decker trains for the first time in Britain, is seen as the greenest and most effective way to speed up travel and to provide the increase in capacity needed to help Britain's economy prosper.

The proposed 535 km Y-shaped route, linking London to Birmingham, Manchester, Sheffield and Leeds and opening in phases from 2026, will not be confirmed until after public consultations.

The public will have their say on the first stage of the route, linking central London to Britain's second biggest city Birmingham, later this year, Adonis said.

The plans have come under fire from some residents along the proposed railway, who fear its construction will destroy areas of natural beauty in central England and disrupt their lives.

The government, which hopes to secure significant private investment to help with the costs of the project, estimates 440 homes will need to be demolished to make way for the link.