Theresa May has warned technology companies that they “can and must do more” to tackle hate material on the internet.

Google has come under fire in recent days after a host of firms suspended advertising with the internet giant amid concerns over extremist videos.

Google has apologised and announced that it was accelerating an ongoing review into the problem.

But a No 10 spokesman said: "It is clear social media companies can and must do more".

He added: “The fight against terrorism and hate speech has to be a joint one. The government and security services are doing everything they can and it is clear that social media companies can and must do more.

"Social media companies have a responsibility when it comes to making sure this material is not disseminated and we have been clear repeatedly that we think that they can and must do more. We are always talking with them on how to achieve that ... The ball is now in their court. We will see how they respond.”

He insisted that he was not saying that online material was necessarily a factor in the radicalisation of the Westminster attacker.

He also declined to give details of what action Mrs May wanted technology companies to take.