The UK leads the world in downloading television programmes, according to internet monitoring company Envisional.

Over the last year Envisional monitored illicit downloads of hit programmes such as 24 and saw an average of 95,000 downloads for recent episodes. Around 18% of shows monitored were downloaded to the UK, closely followed by Australia, but well ahead of the US at around 7%.

The most popular programmes are hit series that air in the US months before they reach screens overseas. In some cases the programmes can be found online within an hour of airing being transmitted on the east coast of America, even before they are seen on the west coast.

The general distribution mechanism is a peer-to-peer system known as BitTorrent, which shares the download across multiple users, so that the more popular a programme becomes, the faster it generally downloads.

“The key to cheap file distribution is to tap the unutilized capacity of your customers,” according to the author of BitTorrent. “Their contribution grows at the same rate as their demand, creating limitless scalability for a fixed cost.”

An hour-long highly compressed programme can be downloaded in a few hours over a typical home broadband connection. The quality is good enough that downloads can be watched comfortably on a computer monitor or, when copied to a CD or DVD, on a television. In some cases high definition versions are available.

“The impact of BitTorrent on digital asset piracy of all kinds cannot be understated,” said Ben Coppin of Envisional, comparing the threat with that of Napster on the music industry.

As with the reports of the demise of the music business, which have been greatly exaggerated, the impact of such video piracy and the potential for “Napsterization” of popular television programmes should not be overstated.

The numbers indicated imply only 20,000 viewers in the UK for a single episode of the most popular programme, which is almost insignificant in terms of television ratings, although perhaps more relevant in terms of potential DVD sales.

The report claims that “it is as easy to download a television show through a web site as to schedule your VCR to tape the episode”. While this may be true for the online cognoscenti, the majority of television viewers might find it equally difficult as setting their VCR.

However, there are opportunities to be exploited to make the process easier through legitimate commercial models, just as the music industry has responded with digital rights managed download services.

The BBC is already experimenting with an internet media player that will use a similar peer-to-peer approach to downloading programmes.