Thirty years after they were first promised, Eurostar services to Scotland were back on the political agenda yesterday.

An influential group of transport experts called for high-speed links through the Channel Tunnel to be extended right through London to Glasgow and Edinburgh.

Greengauge21, a think-tank, believes French TGV technology could cut journey times from London to the Scottish cities to well under four hours, shifting thousands of journeys from air and road to rail.

And the group, which is led by consultant Jim Steer, reckons the infrastructure needed could be put in place for just £11bn, little more than the cost of the most recent revamp of the existing west coast main line.

In a new report, the group said: "It is time for ministers to press the start button in planning Britain's high-speed rail network."

High Speed One, a superfast link between the Channel Tunnel and St Pancras Station, will open on time and on budget in November.

Mr Steer and his colleagues want to see a High Speed Two, a continuation of the service through the English Midlands to Manchester, Glasgow and Edinburgh.

They said: "The development of a second high-speed line can be highly cost-effective. It can attract private sector finance. It will complement and join High Speed One and the wider benefits it will bring to the economy are immense."

About £6bn has been spent on High Speed One. The Greengauge21 report said a London-Birmingham 110-mile section, costing £7.1bn, could represent a first phase of High Speed Two. The other sections - to Heathrow and onwards to the west coast main line - could be added later.

Network Rail and other rail experts prefer the west coast route, which is quicker for both Edinburgh and Glasgow. The Scottish capital, after all, lies to the west of Carlisle, despite the popular perception to the contrary. Iain Docherty of Glasgow University, one of Scotland's leading transport experts, said: "A TGV on the west coast route is eminently sensible. If you want to build a quick link from Glasgow to Edinburgh we could create the 21st century version of the Carstairs junction."

Environmentalists have long supported high-speed rail links from Scotland to the south of England and the continent. Regional Eurostar trains from Glasgow and Edinburgh to Paris were proposed when the Channel Tunnel was being planned in the 1980s.

Eurostar, however, has said it no longer believes such services would be commercial thanks to the massive rise in low-cost flying. Similarly, Nightstar links with the Continent were stillborn, despite £180m being spent on rolling stock which was never used.

There are alternative high-speed surface links between Scotland and England. Some groups favour Maglev technology, wheelless trains that float on magnetic cushions. Only China has embraced Maglev on a commercial basis, a short link to Shanghai's Pudong Airport. The Chinese authorities, however, last month said they would put the technology on hold as they stepped up development of conventional high-speed heavy rail.