WPP supremo Sir Martin Sorrell has called on Google to “step up and take responsibility” for the content posted to its platforms.

Speaking on a panel at the Festival of British Advertising in London on Friday, Sir Martin said the tech behemoth had not done enough to allay advertiser concerns about the safety of their brands on its platforms.

Sir Martin was speaking on a panel that also included Google’s UK managing director Ronan Harris, however, when the topic of ads appearing around hate and terror sites came up, Harris said Google was trying to ““allay [advertiser] concerns by and large”.

However, Sir Martin interjected: “You haven’t allayed their concerns. You can spin this, Ronan, or we can speak the truth,” Sorrell said. “I have three major clients here in the UK who have contacted me recently, personally, and said brand safety is a massive issue and they don’t agree with what you just said,” his comments reported on UK’s Business Insider.

“You have to take responsibility for this as a media company because you are not a passive, sitting there, digital engineer, tightening the digital pipes, with your digital spanner, and not responsible of the flow-through content … you are responsible and you have to step up and take responsibility.