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(CNN) — It moves millions of people around the British capital every day, acted as a giant air raid shelter during World War II and in more recent times sections of it have been transformed to host hydroponic farms.
Now the London Underground is being touted as a stylish new subterranean route for pedestrians and cyclists.
London Underline -- which won the award for best conceptual project at the London Planning Awards last week -- proposes transforming disused tube tunnels into a network of underground pathways that will reduce the pressure on the city's bustling streets.
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The plans also highlight the possibility of offering excess space up for cultural and retail projects.
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"Our concept proposes repurposing underutilized infrastructure to provide quick links between existing tube stations and key London landmarks and destinations," said Ian Mulcahey, managing director of Gensler London, the architecture and design firm behind the idea.
An artist's rendering of an underline passageway show hip young things strolling past an underground coffee shop while a happy cyclist gives the thumbs up. In another image, a graffiti artist crouches down to tag an idle wall with her colorful signature.
"Anything is possible," Mulcahey continued. "Our vision for the London Underline relies on infrastructure that's already in place. We'd like to bring it back to life."
In their submission to the LPA competition, Gensler highlighted the green credentials of the project as well as its transportation benefits. Pavegen technology which transforms footsteps into kinetic energy would help power electricity and WiFi networks in the tunnels, the company said.
On top of all this, Underline could provide the added benefit of helping to reduce accidents involving cyclists on the road.
There were 489 cycle incidents classed as fatal and serious in London's in 2013, according to data from Transport For London, the city's transport authority.
However, some critics and cycle groups have branded the project as gimmicky and not a plan that would make cycling more convenient.
"This is something that rears its head every so often, ideas to put cycle pathways underground or in the sky," said Rosie Downs of the London Cycling Campaign group.
Architect Norman Foster unveiled designs for SkyCycle, a network of elevated bike paths hoisted aloft above railway lines, in early 2014 although little has been heard of the idea since.
Too few tunnels
A spokesperson for TFL also told CNN that even though there are a number of disused stations and tunnels beneath the streets of London there were none of "significant length that are not already part of our operational railway."
Downes said she would rather see "Dutch style" infrastructure put in place on existing road networks to separate cyclists and heavy traffic. And TFL recently granted permission for two new sections of "cycle superhighways" which reserve long stretches of London road for cyclists only.
"The greatest way to encourage cycling is to make it easier for people to plan local trips to the shops or to schools," Downes said.
"Obviously if you are proposing underground tunnels, that's just not going to work," as many bike journeys won't go anywhere near the subway network, she added.
A cyclist rides along a section of London's cycle superhighway.
Yet Mulcahey counters that the the Gensler idea is designed to augment existing cycle infrastructure rather than compete with it.
Even if the London Underline idea doesn't take off, he thinks it could be applied to other cities with large underground networks.
"Commentators from all over the world are reaching out for more information about our proposal, to evaluate it against their own disused infrastructure," Mulcahey said.
"What we are saying with the London Underline is that we need to look at all the spaces that currently exist within cities, and ask ourselves: 'Are we using them in the best way that we can?' If not, what else could we do?"