Some 6.7 million broadband users are potentially exceeding the restrictions set on their "unlimited" packages by fair usage policies.
That is according to a new study by uSwitch.com, which indicated that 39 per cent of users believe they can download as much as they like on their existing broadband deals.
It revealed that more people are unaware of download limits than last year, partly because AOL UK, Sky and TalkTalk are the only major broadband providers to clearly advertise these restrictions.
Despite what millions of users think, the only provider that currently offers a broadband deal with unlmited usage is Sky, however suppliers do not appear interested in following suit.
Jason Glynne, uSwitch.com communications specialist, said: "The solution is easy, broadband companies should not be allowed to class their packages as unlimited if they are not."
Last month, official statistics revealed that there are now 16.5 million home broadband connections in the UK, up 1.5 million (seven per cent)from 2008.