Ofcom is to call for greater regulation of social networks in line with the mobile phone and broadband industry.

The media regulator is expected to unveil plans today for a new system, similar to that seen in the telecoms industry, which would monitor how tech companies such as Facebook and Google deal with complaints.

Targets could be set for how quickly they remove offensive content – and substantial fines issued if they fail to meet these targets.

However any plans would need to be approved by the government.

Chief executive Sharon White is today expected to describe the unregulated nature of large swathes of the internet as a “standards lottery”, in reference to the strict controls which govern TV and radio.

She will say: “Our research shows that people see social media platforms as the single biggest source of online harm – and most people want the rules to be tighter. Trust in them is already weakening.

“As a regulator, we are required to keep audiences safe and protected – irrespective of the screen they watch or the device they hold.

“Without even knowing it, viewers are watching the same content governed by different regulation in different places or none at all.”

Tech companies have long argued that they are merely platforms and not media companies – and are therefore not liable for offensive content published upon them.

Facebook, for example, has around 2.23 billion monthly active users at present, making it extremely difficult to moderate content. However they and other tech firms such as Twitter and YouTube have hired tens of thousands of staff in recent years to improve moderation.

Critics have pointed to the fact that these firms attract massive advertising revenues, far in excess of many traditional media companies, and therefore should be expected to maintain standards.