Virgin Media has successfully trialled broadband speeds of up to 1.5Gb - 240 times faster than the national average.
The speeds have been achieved during trials of Virgin's cable network at 'Silicon Roundabout' in London's Old Street area.
The 1.5Gb download and 150Mb upload trial uses the same infrastructure and technology as Virgin Media uses to provide residential customers with speeds of up to 100Mb, which are being rolled out to over half of all UK homes.
"As people are simultaneously connecting more gadgets to the internet and doing more online than ever before, we wanted to explore what our unique fibre optic network is capable of," said Jon James, executive director of broadband at Virgin Media.
"At speeds of up to 1.5Gb, Virgin Media is delivering some of the fastest broadband in the world and, thanks to our ongoing investment, we're able to anticipate and lead the way in meeting growing demand for bandwidth as future services and applications come online."
Communications Minister Ed Vaizey attended a celebratory event at TechHub in Silicon Roundabout, a community and workspace for technology entrepreneurs.
"It is fantastic to see the fastest internet speeds in the world over cable being trialled here in the UK," he said.
"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."
Other businesses taking part in Virgin Media's 1.5Gb trial include BespokeBanter.com, an online media outfit, and soproductions.tv, a video production company.
The superfast speeds have been made possible due to £13bn of private investment by Virgin Media, who aim to have every cable home in the UK connected to a state-of-the-art fibre optic network by a high-grade coaxial line.
Virgin says its future-proofed infrastructure means consumers will be best placed to access future interactive entertainment and public services, such as remote healthcare and online education, as they're developed.
The DOCSIS2 technology used throughout Virgin Media's network provides a future-proofed platform with theoretically near infinite capacity.
Virgin Media is able to bond multiple downstream and upstream channels together to be used at the same time by a single subscriber to deliver faster speeds. DOCSIS 3.0, the current standard used throughout Virgin Media's network, also incorporates support for Internet Protocol version 6 (IPv6).