More than a 100 advertising companies, including Google and Facebook, are allowed to track visitors to government and other public sector websites, in a clear violation of governments' own data protection rules, a new report highlights. The report by Danish browser-analysis company Cookiebot found that so called ad trackers are used on the websites of 25 EU governments to track user behaviour. Google, YouTube and DoubleClick, Google’s advertising platform are the most widely used trackers on European government webpages.