A spokesman for Prime Minister Theresa May said Google (GOOG) would be attending a meeting at the Cabinet Office later on Friday after the Times newspaper reported that public sector adverts were appearing alongside videos carrying homophobic and anti-semitic messages.

The spokesman said the government had suspended its advertising from YouTube.

“We are waiting for reassurances that they have in place the technical expertise to stop our adverts appearing in the wrong places,” he said.

Other organizations, such as retailers Sainsbury’s and Argos and the Guardian newspaper, said they had also withdrawn their advertising.

“It is completely unacceptable that Google allows advertising for brands like the Guardian to appear next to extremist and hate-filled videos,” a Guardian spokeswoman said.

“We have stopped all advertising through Google with immediate effect until we receive guarantees that this won’t happen in the future.”

Google said in a statement it worked hard to remove ads from appearing on pages or videos with “hate speech, gory or offensive content” and said it had launched a review to give brands more control over where their ads appeared.

“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,” it said in a statement.

“In a very small percentage of cases, ads appear against content that violates our monetization policies. We promptly remove the ads in those instances, but we know we can and must do more.”

Google added that it believed in the freedom of speech and expression on the Internet, even when it did not agree with the views expressed.