There is a significant gap between the broadband speeds offered by different internet service providers (ISPs), new research has revealed.

According to a study by Ofcom in association with technical partner SamKnows, the average broadband speed in the UK is 4.1Mb, despite the average headline speed claiming to be "up to" 7.1Mb.

More than 60 million service performance tests were carried out across 1,600 homes between November 2008 and April 2009 to reveal that just nine per cent of those on 8Mb broadband packages were able to download at over 6Mb.

Furthermore, the study - which focused on the nine biggest UK ISPs - showed that 19 per cent of this group received speeds of less than 2Mb, on average.

Urban consumers received faster speeds than their rural counterparts - 4.6Mb on average compared to 3.3Mb typically - but all customers experienced slowdown during peak hours, usually of around 20 per cent.

Tiscali's "up to" 8Mb broadband deal was found to be the slowest, typically ranging from 3.2 to 3.7Mb in terms of actual speed. Topping the table was Virgin Media, which delivered average speeds from 8.1 to 8.7Mb, followed by O2 which averaged 4.1 to 5.1Mb.

AOL UK posted typical speeds of 3.3 to 3.9Mb; BT of 3.8 to 4.2Mb; Orange of 3.8 to 4.5Mb; TalkTalk of 3.8 to 4.6Mb; PlusNet of 3.8 to 4.9Mb and Sky of 4.0 to 47Mb.

These figures supported the finding that cable broadband customers received noticeably faster connections than those with ISPs using either first or second-generation ADSL technology.

The two slowest providers, Tiscali and AOL UK, are both now owned by Carphone Warehouse, which also operates TalkTalk.