Alcatel-Lucent and BT said speeds of 1.4 terabits per second were achieved during their joint test – enough to send 44 uncompressed HD films a second.
The test was conducted on a 410km (255-mile) link between the BT Tower in central London and Ipswich.
However, it may be many years before consumers notice any effect.
But the breakthrough is being seen as highly important for internet service providers (ISPs), as it means a greater amount of information can be sent through existing broadband infrastructure, reducing the need for costly upgrades.
“BT and Alcatel-Lucent are making more from what they’ve got,” explained Oliver Johnson, chief executive of broadband analyst firm Point Topic.
“It allows them to increase their capacity without having to spend much more money.”
Alcatel-Lucent told the BBC that the demand for higher bandwidth grew by around 35% every year, making the need for more efficient ways to transfer data a massively pressing issue for ISPs, particularly with the growing popularity of data-heavy online services, such as film-streaming website Netflix.
There are faster methods of transmitting data – such as the use of complex laser technology – but this is the first test to achieve such high speeds in “real world” conditions, outside testing labs.