Tiscali has come out bottom of Ofcom's league table of internet service providers, with the lowest measured bandwidth compared with its advertised speed.
The regulator measured broadband speeds of ISPs offering up to 8Mbps and 10Mbps advertised bandwidth.
Tiscali's 8Mbps tariff varied between 3.2Mbps and 3.7Mbps. Other ISPs fared slightly better in the tests, with Virgin Media's fibre-based service coming out top with 8.1 to 8.7Mbps for its 10Mbps service. BT's 8Mbps service varied between 3.8Mbps and 4.2Mbps.
The research, carried out in conjunction with technical partner SamKnows and market research agency GfK, was based on 60 million separate service performance tests in more than 1,600 homes between November 2008 and April 2009.
The Digital Britain report stipulates a minimum broadband speed across the UK of 2Mbps. Although the ISPs surveyed all achieved greater bandwidth than this minimum on average, Ofcom found that the actual speeds received varied widely. Nine per cent of the sample on 8Mbps packages received actual average speeds of more than 6Mbps and 19% received on average less than 2Mbps.
- AOL ("up to 8Mbps"): 3.3 to 3.9Mbps
- BT ("up to 8Mbps"): 3.8 to 4.2Mbps
- O2 ("up to 8Mbps"): 4.1 to 5.1Mbps
- Orange ("up to 8Mbps"): 3.8 to 4.5Mbps
- Plusnet ("up to 8Mbps"): 3.8 to 4.9Mbps
- Sky ("up to 8Mbps"): 4.0 to 4.7Mbps
- Talk Talk ("up to 8Mbps"): 3.8 to 4.6Mbps
- Tiscali ("up to 8Mbps"): 3.2 to 3.7Mbps
- Virgin Media("up to 10Mbps"): 8.1 to 8.7Mbps