Exclusive The UK's second largest ISP, Virgin Media, will next year introduce network monitoring technology to specifically target and restrict BitTorrent traffic, its boss has told The Register .

The move will represent a major policy shift for the cable monopoly and is likely to anger advocates of "net neutrality", who say all internet traffic should be treated equally. Virgin Media currently temporarily throttles the bandwidth of its heaviest downloaders across all applications at peak times, rather than targeting and "shaping" specific types of traffic.

The firm argues that its current "traffic management" policy allows it to ensure service quality at peak times for 95 per cent of customers while still allowing peer-to-peer filesharers to download large amounts of data.

The details and timing of the new application-based restrictions are still being developed, Virgin Media's Kiwi CEO Neil Berkett said in an interview on Monday following the launch of his firm's new 50Mbit/s service. They will come into force around the middle of next year, he added.

A company spokesman later declined to provide more detail on the CEO's comments. He said: "Broadband has become integral to delivering home entertainment services and with data consumption growing rapidly, we are exploring new ways to enhance our product offering. Part of this involves intelligent monitoring and understanding the way people use our broadband service."

Virgin Media has launched its 50Mbit/s broadband package without any form of traffic restriction, but it said it would do so as take-up increases. Berkett said top package customers would be reined in from the middle of next year; the same time he proposes to introduce application-based restrictions.

Asked why the firm would ditch its system of choosing who to throttle based on their total usage, in favour of singling out BitTorrent, Berkett said: "I think it's an issue of fairness."

BitTorrent is a major problem for network operators, who characterise its heavy users as "bandwidth hogs". The US provider Comcast was last year summoned to Congressional hearings over measures it took to reduce the impact of BitTorrent on its network. The Federal Communications Commission subsequently banned the practice and fined Comcast, prompting celebrations from net neutrality campaigners.

In the UK there has been no regulatory opposition to application-based bandwidth restriction. Major ISPs including BT and Carphone Warehouse use specialised "deep packet inspection" (DPI) equipment to monitor and manage the protocols running over their networks.

As recently as June this year, however, Virgin Media told The Register it had no plans to follow suit. "Our policy does not discriminate internet traffic by application and we have no plans to do so," it said.

That statement was made in response to the suggestion that Virgin Media's purchase of DPI kit from the Israeli firm Allot was a precursor to restricting bandwidth-hungry applications such as BitTorrent.

"Whilst we do use equipment from Allot within parts of our cable network, this is used to build usage metrics and does not affect customers' service in any way. It is certainly not used to do any form of packet shaping or change internet traffic priorities," came the denial.