Communications regulator Ofcom has revealed that BT’s underground and overhead cabling infrastructure could support significantly more network capacity than is currently used.

Ofcom called on the telco to make this unoccupied space available to its competitors, so that they might build super-fast broadband services (defined by Ofcom as enabling download speeds of at least 24Mbps) without the need to build their own physical infrastructure.

In a report published yesterday, Ofcom said that around half of BT’s duct network – underground pipes through which much of its cabling runs – has space for more cables. It added, however, that “availability is highly variable across the country and the practicalities of using BT’s ducts and poles have yet to be worked through." Ofcom’s report also found that 85% of telegraph poles could support new cables.

A story in the Financial Times earlier this year claimed that BT was willing to let competitors lay cable in its duct network to support super-fast broadband. And earlier this month, the Times report that BT had called on Virgin Media to open up its duct infrastructure.

The watchdog will issue new rules governing infrasructure sharing later this year. “At this early stage in the development of super-fast broadband, other communications companies indicate that they may prefer initially to be able to deliver services over BT’s network rather than build their own," it said this week.

"Therefore we propose that BT should make wholesale virtual unbundled local access (VULA) available to other communications companies on the same basis as to itself."

In yesterday’s budget speech, Chancellor Alastair Darling confirmed the government’s plan to levy a 50p monthly tax on landlines, which he said would “unlock private investment and enable 90% of the country to access the next generation of superfast broadband by 2017.”