The Guardian was one of the first to announce on Thursday that it was withdrawing all of its advertising from Google and YouTube after ads promoting its membership program appeared next to "extremist material", including YouTube videos of American white nationalists, a hate preacher banned in the United Kingdom, and a controversial Islamist preacher. "We rely on governments to notify us of content that they believe is illegal through official processes, and where appropriate, will restrict it after a thorough review", a YouTube statement said.
A number of advertisers - including the British government - have now pulled their ads from YouTube.
Analysis by The Times showed that blacklists which are created to prevent digital adverts from popping up next to extremist content, are not working.
Google is to be summoned before the government to explain why taxpayers are unwittingly funding extremists through advertising, The Times can reveal.
In a letter sent to Google executive Matt Brittin, he said that it was vital for Google to "uphold the highest standards in terms of openness, transparency, and measures to avoid advertising fraud".
The Times suggests the misplaced advertising is generating "tens of thousands of pounds a month for extremists" and blamed ad agencies for "pushing brands into online advertising to boost their own profits". "However, with millions of sites in our network and 400 hours of video uploaded to YouTube every minute, we recognize that we don't always get it right", he said. Ronan Harris, managing director of Google UK, said the company would be making changes in the coming weeks to give brands more control over where their adverts appeared. This comes after the United Kingdom government chose to move away from TV advertising and focus more funding on digital advertising on outlets like YouTube, with the Cabinet Office saying these outlets are a "cost-effective" way of reaching mass audiences. Given the fact that companies like Google make billions each year, it seems logical to demand better policing so that they don't promulgate of hateful extremist content or fake news.
That also led to Google to remove PewDiePie from a "family-friendly" ad network he was previously included in and cancel his YouTube Red show.
Google was summoned to appear in front of Cabinet Office ministers on Friday.
Havas Worldwide is pulling all spending from Google and YouTube in the United Kingdom, citing the desire to have more control of its inventory in hopes of keeping brands away from inappropriate or offensive content.
"The decision of our United Kingdom team to pause activity with our partner Google is a temporary move made by the local team on behalf of our United Kingdom clients and their specific needs", she said in an emailed statement.
All government-funded YouTube advertising remains on hold until further notice.
Sir Martin Sorrell, chief executive of the world's largest marketing services group WPP, was critical of Google, but fell short of blacklisting the company from its United Kingdom advertising schedule. In a very small percentage of cases, ads appear against content that violates our monetization policies.