Regulators in Europe and the UK have opened an antitrust probe into a deal between Google and Meta on online advertising, in the latest effort to tackle the market power of the world’s biggest technology companies.

The move follows US antitrust investigators who are also probing an agreement informally known as “Jedi Blue.” The search engine giant and Facebook’s parent company have been accused of working together to carve up advertising profits, acting together to buttress their businesses.

The EU and UK probes represent the latest assault on Big Tech from global regulators that are also preparing to unleash new rules designed to challenge the primacy of groups such as Google, Meta and Amazon. In response, US tech groups have launched lobbying efforts in Washington and Brussels in an effort to protect their interests.