Google has apologised for allowing adverts to appear alongside offensive videos on YouTube.
It comes as high-profile companies such as Marks & Spencer and HSBC pulled advertising for British markets from Google sites.
Speaking at an industry event, European boss of Google, Matt Brittin said: "I would like to apologise to our partners and advertisers who might have been affected by their ads appearing on controversial content".
Mr Brittin said Google had made a commitment to doing better and would simplify advertiser controls, add safer defaults and increase investment to enforce its ad policies faster.
The Government has already suspended its advertising on YouTube after some public sector ads appeared next to videos carrying homophobic and anti-Semitic messages.
Britain is the largest market for Alphabet Inc's Google outside the United States, generating $7.8 billion mainly from advertising in 2016.
WPP, the world's largest advertising firm has said it was talking to clients and media partners such as Google, Facebook and Snapchat to find ways to protect brands.
"We have always said Google, Facebook and others are media companies and have the same responsibilities as any other media company.
"They cannot masquerade as technology companies, particularly when they place advertisements," said Martin Sorrell, the founder and head of WPP.
Last week Google executives were called in to answer questions from the advertising industry over the issue.