Ofcom's research into fixed line broadband speeds has revealed the ISP heroes and villains, with Virgin's 10Mb service head and shoulders above many rivals.

The research, conducted with SamKnows, took samples from ISPs offering fixed broadband speeds of between 8Mb and 10Mb.

Virgin's fibre optic cable was the only one at the higher level – but the research shows that it provided an average speed of 8.1 to 8.7 Mbps – or 81 to 87 per cent of the advertised speed.

The likes of Sky and O2 also gained some credit, with the former's 8Mb line offering between 50 and 59 per cent (4.0 to 4.7Mbps) of what was advertised and the latter offering between 51 and 63 per cent (4.1 to 5.1Mbps).

Bottom of the pile was Tiscali with 3.2 to 3.7Mbps and AOL with 3.3 to 3.9Mbps.

Virgin was unsurprisingly delighted with the results, with a spokesman telling TechRadar: "It's what customers get, not what their ISP claims, that counts.

"Today's report emphatically demonstrates that the "up to" marketing claims of most copper-based broadband providers are not to be trusted, with most major ISPs delivering less than half of what they promise.

"Virgin Media delivers more than any other major ISP - even our cheapest broadband tier delivers double the average of our major competitors - and we are committed to making all of our marketing better reflect the actual experience our customers get."

Both O2 and PlusNets tests were conducted on a smaller sample than the other ISPs.

ISP and package - average speed

AOL ('up to' 8Mbit/s) - 3.3 to 3.9Mbps

BT ('up to' 8Mbit/s) - 3.8 to 4.2Mbps

O2 ('up to' 8Mbit/s) 4.1 to 5.1Mbps

Orange ('up to' 8Mbit/s) 3.8 to 4.5Mbps

Plusnet ('up to' 8Mbit/s)* 3.8 to 4.9Mbps

Sky ('up to' 8Mbit/s) 4.0 to 4.7Mbps

Talk Talk ('up to' 8Mbit/s) 3.8 to 4.6Mbps

Tiscali ('up to' 8Mbit/s) 3.2 to 3.7Mbit/s

Virgin Media ('up to' 10Mbit/s) 8.1 to 8.7Mbps