British web users are still failing to secure their wireless internet connections, leaving themselves open to unauthorised use of their connection, according to research by Moneysupermarket.com.

In a survey of 1,992 people, the price comparison site found that just under a fifth of broadband users were failing to protect their wireless routers.

Rob Barnes, head of broadband and mobile phones at Moneysupermarket.com, said: "People are learning to be safe online but those using wireless can undo all that by leaving their network unprotected. An unsecured internet connection is just the same as leaving your front door open."

The consequences can be severe if a wireless router is 'piggybacked'.

This is where broadband users connect to someone else's wireless router to gain free access to the internet. It can lead to identity theft, fraud and illegal downloading. About one in ten people admitted to using someone else's wireless internet connection without permission on a regular basis in the past 12 months to download films and music.