Virgin Media, the UK cable broadband operator, announced that it has completed a successful trial delivering speeds of 1.5Gpbs over its existing cable infrastructure. The trial was conducted on a single road in London called Old Street, part of an area that has been dubbed the ‘Silicon Roundabout’ by members of the local tech community known as the ‘TechHub’.

The demontration was just a showcase and will not be a consumer reality anytime soon, but the speeds were achieved by bonding together multiple downstream and upstream channels of Virgin’s DOCSIS 3.0 cable network. Virgin Media’s consumer cable offering currently tops out at 100Mbps, and it recently announced that this was now accessible by 25 per cent of the UK’s population.

The 1.5Gbps speeds are some 240 times the UK’s average broadband speed, which a report from UK regulator Ofcom revealed at being 6.2Mbps during November and December 2010.

To celebrate its high speed achievement the cable company held an event at the TechHub, which was attended by UK Communications Minister Ed Vaizey.

“It is fantastic to see the fastest internet speeds in the world over cable being trialled here in the UK, Vaizey said at the event. “This exciting development will help attract new companies and entrepreneurs to the area, bringing new jobs and growth to this part of the capital. Last year the Prime Minister set out our ambition for London’s East End to become a world-leading technology city to rival Silicon Valley. Developments like Virgin Media’s will help make this ambition a reality.”

Virgin Media was recently told by the UK’s Advertising Standards Authority not to run 10 adverts again after upholding complaints from rivals over the accuracy of claims in the ads. In one ad Virgin claimed that its service was twice as fast as that of rival BT’s but the ASA agreed that this did not take into accounts BT’s faster Infinity service. BT Infinity and Virgin Media’s service are hybrid optical networks – fibre optic to a local cabinet with coaxial and copper from there to the premises.

A UK startup called Hyperoptic recently announced that it would be launching a 1Gbps fibre-to-the-premises service in the UK from September, but has not revealed any details on pricing.