THE amount of data travelling across the internet is growing so fast that the network could become overloaded and grind to a virtual standstill, experts have warned.

Online video is the biggest drain on the capacity of copper wires originally intended to carry only voice calls.

But demand for YouTube, the BBC's iPlayer and other data-hungry internet TV services is surging. Last year it was claimed that YouTube consumed as much bandwidth in a year as the entire internet took up in 2000.

The worst-case scenario is not so much a crash as a global gridlock in which email, social networks and internet sites slow to a crawl.

Capacity

Research has shown US internet traffic is increasing at more than 50 per cent a year, with capacity expanding at only about 40 per cent a year.

Internet service providers have been criticised for striving so hard to undercut each other on price that they are failing to invest in the infrastructure necessary to keep up with demand.

Although BT is spending £10bn on one of its biggest upgrades, turning its old networks into a `21st-century network' to launch at the end of this month, it will not address the issue of the `last mile' copper into the home.

Replacing this with high-speed fibre optics would cost an estimated £20bn.

BT spokesman Mike Bartlett said: "There will not be a fibre-to-the-home network in the next 20 years. It would take many years, cost billions of pounds, involve digging up all the roads and we don't know if people really want it."