We all know by now that ISPs' promised broadband speeds should be taken with a pinch of salt. But comparison site Broadbandchoices.co.uk claims to have exposed the full extent of the disparity between what individual ISPs claim they offer and what they deliver.

According to BroadbandChoices' July survey - based on speed tests performed by users - Tesco customers are most likely to achieve the broadband speeds they pay for. But even the supermarket giant has little to be proud of – its customers get 53.8 percent of the maximum speed Tesco promises them. Broadband subscribers using other ISPs get a far worse deal, however - on average they get 39 percent of the speed promised to them.

So where does your ISP stand? Here's the full list:

1. Tesco 53.8%
2. AOL 48.3%
3. Virgin Media 41.1%
4. Tiscali 37.3%
5. Madasafish 35.3%
6. Sky 34.9%
7. Pipex 33.8%
8. Orange 32.9%
9. Eclipse Internet 32.5%
10. Karoo.co.uk 32.3%
11. BT 30.8%
12. Demon 30.3%
13. TalkTalk 29.9%
14. Plus Net 28.5%