Anti-racism campaigners have called for Twitter to improve its technology after tweets on the platform containing racist language remain published.

Tweets dating at far back as 2014 have been highlighted by Press Association which use racist language in reference to Premier League stars Danny Welbeck and Raheem Sterling.

Twitter said that its proprietary-built tech finds abusive content but the company, and its CEO Jack Dorsey, have always conceded that it is not perfect and works more effectively with human intervention.

A Twitter spokesperson said that "Abuse and harassment - no matter who the victim - have no place on Twitter."

Anti-racism campaigners Kick It Out have said that the technology in place on Twitter’s platform is "evidently" not working.

“Twitter says abuse and harassment has ‘no place’ on its site, but it is obvious that there really is a place for it there and in our view the problem is getting worse,” a spokesperson for Kick It Out said.

“Footballers, like anyone in society, are entitled to go about their work without being abused, intimidated or trolled.”

This week the Government has issued a white paper which suggests new measures to better regulate internet companies who fail to protect their users.

The measures include an independent regulator who will have the power to impose fines on firms for breaches and to potentially prosecute.