The UK’s Competition and Markets Authority is expected to launch an in-depth investigation this week after Microsoft decided not to offer any remedies at this stage. The CMA became the first global antitrust regulator to sound the alarm over the transaction, giving Microsoft five days to come up with undertakings that would resolve its concerns or face an extended “phase 2” probe.

The companies have already been in talks with regulators in Brussels since the deal was announced in January, in what is known as the pre-notification stage.

This means that regulators and others involved in the deal expect a prolonged EU investigation once Microsoft officially files its case in Brussels in the coming weeks. It means that the deal is a long way from ending up with Vole in charge of the gaming company.

Sony last week accused Microsoft of misleading the games industry and regulators about its commitments to keep Call of Duty on PlayStation consoles. It said Microsoft had only offered to keep releasing Activision’s hit game on PlayStation for a limited number of years.

Microsoft apparently is not offering any remedies to the CMA at this stage because there were no obvious commitments the UK regulator would be likely to accept such as commitments to maintain access to a product or service -- at least at this point in the investigation.

The Activision deal comes at a time when regulators around the world are concerned they have not been as interventionist as they should have been with regards to previous Big Tech deals.