In a blog entitled Improving our brand safety controls, Harris was responding to the recent reports in The Times that brands were unwittingly funding terror groups when their online ads were placed against extremist content on sites such as YouTube.

Harris said the company recognised the need to have strict policies that define where Google ads should appear to ensure ads did not appear on pages or videos with hate speech and offensive content.

He defended the business by saying that “in the vast majority of cases, our policies work as intended” but went on to say “we’ve heard from our advertisers and agencies loud and clear that we can provide more robust ways to stop their ads from showing against controversial content”.

Google has begun a thorough review of its ad policies and brand controls said Harris and it would be making changes in the coming weeks to give brands more control.

Paul Bainsfair, IPA director general said of the latest reports of ad misplacement: “It is very disappointing to see further evidence of corporate and now government ads appearing adjacent to questionable or unsafe content. We are also fast-tracking our discussions in this area, particularly with Google. And last week we coordinated a mass multi-buying point email to online inventory suppliers about JICWEBS’ brand safety compliance which has led to many more signing up.”