£1.1bn rail electrification planned

The project, called for by rail bosses for several years, involves the Great Western main line between London and Swansea and the route between Manchester and Liverpool.

The phased work, which will begin immediately and is due to take eight years to complete on the major route and half that on the other, is the first major electrification project for 20 years.

Officials said it could shave 19 minutes off the journey time from London and Swansea as well as increasing rush hour capacity by at least 15%, and bring Manchester 14 minutes closer to Liverpool.

As well as being less likely to break down, the new trains would also emit up to 35% less carbon per passenger mile than diesel locomotives - and produce zero emissions at track level.

The work would pay for itself over the long-term, officials said, through lower train leasing, maintenance and operating costs.

Upgrades for other lines including the Midland Mainline between London and Sheffield and between Preston and Manchester and Liverpool will be considered in the coming months.

Gordon Brown said: "To build a better Britain, we must be bold, innovative and forward-looking and invest with confidence in our country's transport infrastructure, jobs and industry. This electrification programme is vital to building a 21st-century transport system."

Transport Secretary Lord Adonis outlined potential knock-on benefits of the electrification, saying: "In particular it would be possible to run Crossrail services west of the existing proposed terminus at Maidenhead, through to Reading. I look forward to discussing with the Mayor of London, Boris Johnson, the potential for developing new services and integrating these major Crossrail and electrification programmes.

"Electrification of the Liverpool to Manchester line also makes possible the through-running of electric trains from Manchester Airport and Manchester to Scotland."