Internet sites that rely on user-generated video content should adopt watershed viewing hours and a cinema-style age rating system to protect children from porn and violence.

An influential committee of MPs also recommended that sites such as YouTube should do more to screen unsuitable content before publication to protect youngsters from the internet's "dark side".

The report, carried out by the Culture, Media and Sport Committee, said that curbs and closer vetting are required to avoid websites unwittingly publishing pornography, child abuse and other illegal content.

The committee wants postings containing sex, bad language or violence to be blocked before 9pm, and warned that ministers would "act accordingly" unless an industry body is set up to increase self-regulation.

The recommendations come hot on the heels of an alleged gang rape that was viewed 600 times on YouTube before being pulled.

YouTube owner Google said in response to the report that it reviews half of all material flagged by other users as inappropriate within 30 minutes and the majority of other postings within an hour.

"For YouTube we have strict rules on what is allowed, and a system that enables anyone who sees inappropriate content to report it to our 24/7 review team and have it dealt with promptly," the company said in a statement.

"We educate our community on the rules and include a direct link from every YouTube page to make this process as easy as possible for our users.

"Given the volume of content uploaded on our site, we think this is by far the most effective way to make sure that the tiny minority of videos that break the rules come down quickly."