For years, ever more extreme films – sold as either sport or music videos but with content such as cage-fighting, nudity and self-mutilation – have been available to buy without a certificate. This has allowed youngsters to get hold of them, often without parents realising their content.
But MP Andrew Dismore will this week push to tighten the law which allows these films to be exempted from the usual classification system, under the House of Commons' 10-Minute Rule.
At present, videos and DVDs primarily concerned with sport, religion or music do not have to carry a classification, but this has allowed material unsuitable for children to slip through.
These have included the cage-fighting DVD UFC Best of 2007, a combat video which is available on the high street to any child because its distributor has, legally, claimed exemption from classification. It means there is no age rating or consumer advice.
Other exemptions have included DVDs from the bands Motley Crue and Slipknot.
Conservative Culture spokesman Jeremy Hunt last month called for the law to be redrawn. Now Mr Dismore is to begin the process of closing the loophole, introducing classifications.
He said: "Responsible video companies and distributors will get an age rating but some others will not.
"The problem is that (currently] many of these are marked on shelves as E for exempt … for something like a martial arts film it is very misleading."
A spokeswoman for the British Board of Film Classification said: "We do not have any powers to require these DVDs to be submitted for classification. We believe that it is important that material which will be attractive to young audiences should be properly labelled to enable parents to know their children are protected."