The claim has been made after a decision to put the hi-technology Pendolino trains through their paces on the route between Edinburgh and King's Cross station.
It could provide a major boost for the route by drawing commuters and leisure travellers away from budget flights.
Train manufacturer Alstom said the dramatically faster service could be achieved by using the electric train's tilting technology to accelerate at up to 140mph round the bends of the East Coast Main Line. In March, it tested a Class 390 Pendolino on the full length of the route, the first time a tilting train has been used on the cross-border service.
Business leaders welcomed the move. Liz Cameron, chief executive of the Scottish Chambers of Commerce, said: "Upgrade of the East Coast Main Line to allow for tilting trains is another option that could have great benefit for Scottish travellers. Cutting our journey times to London will make it easier to do business.
"There is potential for this upgrade to be completed far sooner than high-speed rail can reach Scotland – it is therefore an option that should be out there and under discussion by all of us looking to improve our transport connectivity."
Alstom said Pendolinos can replace East Coast's fleet of 31 electric InterCity 225 trains, which were introduced to the route in the 1980s and are due to be overhauled or replaced in the next 10 to 15 years. It would require a potential multi-billion pound upgrade of the East Coast Main Line, which does not have the infrastructure in place to allow trains to tilt.
The time savings would be more dramatic for cross-border services and could be achieved earlier than those offered by the UK Government's £32.7 billion High Speed 2 programme.
Tim Bentley, Alstom's managing director, said this could be achieved using "in-cab" signalling known as the European Rail Traffic Management System (ERTMS), which is due to be introduced on the East Coast Main Line later this decade.
"We think there is a credible view that the 390 can take 50 minutes off King's Cross-to- Edinburgh with 140mph tilt in the right places using ERTMS," he told Rail magazine. "But do the operators and Network Rail have these plans?"
Pendolinos were first introduced to the rail network in 2002 by Virgin Trains, which has expanded its fleet to operate on the West Coast Main Line between London and Glasgow.
The trial has generated considerable interest in the rail industry and is being studied by the Department for Transport.
A spokesman for operator East Coast said that although the train did not tilt during the trial run, it showed that its use on "technically feasible".
He added: "We've seen a 36% increase in first-class passengers since the new timetable was introduced in May 2011."
The Department for Transport is preparing to announce details of its programme to replace the ageing diesel trains that connect London to Edinburgh, Aberdeen and Inverness. But it has not decided on a strategy to replace the electric trains and a spokeswoman declined to comment on Alstom's proposals.
Network Rail said the use of Pendolinos on the East Coast Main Line would depend on new in-cab signalling being in place.
A spokesman said: "Network Rail is drawing up plans for the upgrade of signalling on the East Coast Main Line – which, subject to government approval, could start in 2018/19.
"The new in-cab signalling system we propose could allow faster, more frequent and a greater number of services on this vital rail route."
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