UK cable users enjoy significantly higher broadband speeds than those on ADSL, according to a study carried out by broadband comparison firm, BroadbandChoices.

The comparison firms Speed Tester survey results – taken from over 100,000 tests last month – show that cable customers enjoyed an average of 47.5 per cent of their promised speeds, compared to an average of 37.7 per cent for ADSL customers.

The revelation comes as UK cable provider, Virgin Media, began testing 50Mb speeds – more than double the top speeds available over the BT’s own network that competitors use. Virgin’s top commercial speed is currently 20Mbps.

However, Michael Phillips, BroadbandChoices.co.uk product director, said that although Virgin will be offering the fastest speeds in the UK, traffic shaping could slow users down considerably.

“Virgin Media announced its traffic shaping policy earlier this year, and even on the top 20Mb package, customers could find themselves throttled to only 5Mb during peak hours – when obviously, people are most likely to be using the internet.

Phillips believes that Virgin is looking to regain some of the 40,000 customers that defected after Sky pulled its basic channels, with applications that need much faster broadband. “Few other providers can offer the type of speeds needed for high-definition video-on-demand and home surveillance but using these applications could see customers’ speeds throttled and there is little point in a 50Mb connection that is cut each time you use it,” he said. “For example the Broadband XL package at 20Mb has a peak-hour allowance of 3GB which could be exceeded after little more than 20 minutes if the connection was running at top speed. After this time, the connection would be limited to 5Mb for the next four hours. Virgin Media said that this policy would only affect the top five per cent of downloaders but marketing itself as a super-fast broadband provider for bandwidth-hungry applications – and even introducing some of its own – will see increasing numbers of people affected by this,” said Phillips.