The strategy behind the next 12 years of road and rail building, as well as the clearest indication yet of the future of road pricing has been revealed by the Transport Minister Ruth Kelly.

Her latest framework document, which was launched today, outlines the Government’s thinking for delivering what it says is a green yet economically sensitive transport system for the coming two decades.

The strategy document adopts a ‘you can have your cake and eat it’ solution that will see the UK continue with strategies such as expanding more motorways to accommodate the growing number of cleaner cars manufacturers will be forced to develop.

“This document highlights the inadequacies of the recent Transport White Paper, released with such fanfare earlier this summer,” said the Liberal Democrat shadow transport secretary Susan Kramer.

“This announcement seems to be a list of every transport idea ministers have read on a website, instead of being a coherent vision for Britain’s future transport system.”

However, Transport Secretary Ruth Kelly, said the strategy document gives "the opportunity to deliver, for the first time, a pro-green/pro-growth agenda for transport in the short and medium-term".

"Nice words, but the time for words is past. We need action. These ideas must translate into real world improvements, and right now it's not clear how they will,” Stephen Joseph, executive director of Campaign for Better Transport, said.

“We're concerned the department's continuing road building programme and aggressive airport expansion plans will fuel climate change."

The minister argues that forcing the pace of technological improvements and addressing behavioural change will be the keys to achieving at least a 60% reduction of CO2 emissions by 2050.

The document clarifies that spending over the next six years will be focused on Britain’s most congested routes. Beyond then, the document shows that over £20 billion could be allocated to as yet unnamed transport projects.

The Government aims to get businesses to share the cost in an attempt to make the £20 billion go further.

While it is strong on direction and policy, the document contains little that has not already been announced.

Road pricing is still clearly on the agenda, as is a heavy investment in the national road network, with a stronger emphasis on cities and on public transport solutions.

Much of the focus is on urban areas where buses get high priority: investment will be directed to public transport such as bus stations, guided bus and trams, local road improvements, which will benefit both freight and passengers, and traffic management schemes including measures to enable bus priority, says the report.

As already announced hard-shoulder running on motorways will be rolled out, although initiatives such as widening the M25 will still be honoured.

The Government will publish a transport Green Paper and begin a formal consultation process in the spring 2008.