New line "matter of dates" - Minister
A decision on a new UK south to north high speed rail line will be made next year.
Lord Adonis, minister of state for transport said it was "largely a matter of dates."
He told the National Rail Conference: "It will come; the only question is whether it comes in the next 15 years or the next 50.
"A huge amount is at stake for our economy and our society in deciding between the two."
Lord Adonis said while Japan, France, Spain, Germany and Italy have growing high speed networks but the UK had only the 68-mile stretch High Speed One for the Eurostar service to the continent.
The minister, who has just completed a five day rail tour around the UK, said Britain had set up in January the High Speed Two company to draw up a firm route.
This would include a line from London to the West Midlands, with corridor options for extending it beyond to the north-west, West Yorkshire, the north-east and the central Scottish conurbations.
Lord Adonis said the company was due to report by the end of the year.
"We intend to consider the report immediately after its receipt, and to consult the other political parties upon it, with a view to indicating a definite way forward in the early part of 2010.
"The decision we take - on whether, and how, to proceed - will be the most important transport decision we take over the next year."
He said the challenge was to "boost capacity, slash journey times, and attract significant numbers of new passengers to the railways."
He added: "We need to encourage modal shift by getting people out of cars and planes, and so help to reduce transport's overall carbon footprint.
"Proceeding with high-speed rail will be enormously challenging - not only on a political level, in terms of decisions about investment and phasing, and generating the cross-party consensus which I believe is vital to such a major long-term infrastructure project, but also in terms of planning and engineering."