By Will Smale
Business reporter, BBC News
Shanghai's maglev train started commercial service in 2003
When it comes to the railways, the UK has an unrivalled reputation for leading the way in new technologies.
Unfortunately, it is equally renowned for all too quickly abandoning such new advances as too impractical or expensive, only to see other nations go on to prove their success.
One of the most recent such developments that Britain was first to implement - and then abandon - is magnetic levitation or maglev trains.
These are super-fast trains propelled by the force of electric-powered magnets.
Using a combination of magnetic attraction and repulsion for lift and forward movement, they literally float a few centimetres above specially-built tracks.
Because there are no wheels in direct contact with the tracks, friction is substantially reduced. As a result, maglev trains can reach speeds significantly higher than conventional railways - more than 430 km/h (260mph).
Maglev trains are back in the news in Britain after shadow chancellor George Osborne said the UK should follow the lead of China, Germany and Japan and look at the technology.
However, he failed to mention the fact that Britain once had the world's first commercially operating maglev railway.
From 1984 to 1995, it shuttled passengers at Birmingham International Airport 600m from the main terminal to the nearby railway station.
But after 11 years in operation, it was hit by reliability problems and replaced by a conventional system.
Today, the world's only operating maglev railway is at Shanghai International Airport in China, designed by German firm Transrapid.
Since it came into service in 2003, it has taken just eight minutes to complete the 30km (19-mile) journey between the airport and Shanghai city centre.
Germany and Japan are now racing ahead with further developments in maglev technology, and both have plans to install their own lines.
China also continues to have aspirations to develop a wider maglev network.
Meanwhile, the UK government and track operator Network Rail have no current plans to look at maglev again.
So why has Britain turned its back on maglev while other nations are very excited by the technology?
Maglev trains can reach speeds in excess of 260mph
In a word - price. Installing a maglev system is more than five times as expensive as traditional railway systems.
The cost of the maglev railway in Shanghai worked out at a whopping $63m (£33m) per mile.
This compares with the $11m-per-mile cost of recent extensions to France's traditional high-speed rail network.
Maglev lines are more expensive because they are significantly more complicated, involving a continuous system of magnets.
Other concerns include doubts about the long-term reliability of maglev systems, and the fact they are completely incompatible with traditional railway lines - a standard train cannot run on maglev tracks and vice versa.
For these reasons, Network Rail says it will stick with traditional trains and tracks.
"Network Rail believes that the incremental benefits of speed provided by maglev are unlikely to generate enough additional passenger revenue to justify the expected higher cost or the risk of unproven technology," says a Network Rail spokesman.
"For the UK, traditional high-speed technology can deliver fast enough journey times to attract passengers off planes and onto trains."
Independent rail expert Christian Wolmar agrees with Network Rail, saying there are "too many negatives" to maglev.
"There are three main problems with maglev. Firstly, it is not a tried and tested technology," he says.
"Secondly, it cannot run off normal lines, so you would have to build a new maglev line from scratch, which would be massively expensive.
Japan and Germany are leading development of maglev systems
"Thirdly, it is so expensive. You are taking about needing absolutely massive passenger numbers to recoup the costs.
"Is maglev a technological dead end or is it the future? I think the jury is out, but my hunch is that it is not a viable technology, particularly in this country."
Yet others insist that switching to maglev should be the future for UK railways, and would greatly increase passenger numbers by slashing journey times.
Dr Alan James, chief executive of UK Ultraspeed, the company pushing for maglev trains to be introduced in the UK, says it could play a vital economic role.
"The country's international competitiveness demands a world-class national transport infrastructure," he says.
"Ultraspeed's radical transformation of strategic infrastructure would also 'rebalance' Britain, by making the regional economies of the English north and metropolitan Scotland more accessible to, and competitive in, the global economy."
It's still unclear whether the UK is missing out by shunning maglev, but Britain has been caught out before by its attitude to railway innovation.
Back in the 1970s and early 1980s, the UK was one of the leading developers of tilting trains.
As their name suggests, they tilt when going round bends, allowing for faster speeds.
Despite trying out a number of what were then called Advanced Passenger Trains, state-owned British Rail quickly mothballed the technology, blaming a number of technical problems and lack of support from government.
Yet where the UK gave up, other countries continued to develop tilting trains.
Fast forward to today and Virgin Trains' West Coast mainline runs tilting trains - designed and built in Italy.