Building a rapid rail link from High Speed 2 to Glasgow and Edinburgh could cost more than £25bn, a report has revealed.
The study, by HS2 promoter HS2 Ltd for the Department for Transport, found 312km of new railway would be needed for the preferred route to allow trains to travel from London to the two Scottish cities at speeds of up to 400kmph.
It found that such a line would slash journey times from London Euston to Glasgow or Edinburgh to two hours 50 minutes. This is down from typical journey times in excess of four hours to either city at present, and of more than three and a half hours even when HS2 is in place.
The study said the line would start north of Manchester at the top of the western leg of phase two of HS2. It would weave between settlements to Preston before following the existing M6 corridor to Lancaster and passing to the east of Carlisle.
The proposed line would then follow the West Coast Main Line past Lockerbie, and join a separate high speed line that the study assumes would be built between Edinburgh and Glasgow.
Total cost would be £22bn to £25bn plus the cost of the Edinburgh to Glasgow line.
Between the Lake District and Yorkshire Dales National Parks “deep cuttings, viaducts and tunnelling would be required to negotiate the topography”. The design speed has been reduced in sections to as little 200kph to allow the route to follow natural contours more closely. The line would cross the M6 and the West Coast Main Line in places.
The study found that achieving a three-hour journey time from London to Glasgow and Edinburgh through upgrades to existing lines would require 220km of bypasses on the West Coast Main Line at a cost of up to £19bn.
A separate report by Transport Scotland found that the benefits of a high speed rail route between Glasgow and Edinburgh were not sufficient to justify the “very high cost” of building it as a free standing scheme.
The Transport Scotland study added that a high speed route between Glasgow and Edinburgh was “possible” but that its feasibility was “dependent on a commitment to extend HS2 into Scotland”.
Westminster and Holyrood agreed to carry out further work next year with an aim of getting a three-hour journey time in place.
UK government HS2 minister Robert Goodwill said: “Scotland will benefit from HS2 from the day it opens, with shorter journey times to London from the start. Once the full Y-network opens, it will only take around three hours 38 minutes to reach London from Glasgow and Edinburgh.
“This report looks at ways we can build on these improvements and I thank HS2 Ltd for this work. Together with the Scottish government, we will be asking Network Rail to identify any options with a strong business case, for consideration for inclusion in future plans.”
Scottish government infrastructure secretary Keith Brown said: “I now have a firm commitment that development work will begin during the current control period towards getting journey times between Scotland and London down to three hours or less.
“High speed rail will bring billions of pounds worth of benefit to Scotland’s economy and an infrastructure project of this magnitude – possibly the biggest Scotland’s ever seen – means jobs, investment, benefits for the economy and benefits for the environment.
“This plan will bring to life our target of three hours or less Glasgow and Edinburgh to London train journeys, which will lead to a significant move from air to rail, bringing big reductions in carbon emissions.”