The boss of Britain’s competition regulator is to resign amid frustration among ministers that he has not sought to take advantage of Brexit.

Andrea Coscelli, who has led the Competition and Markets Authority (CMA) since 2016, will leave the post in July, the watchdog said.

His departure will be seen in political circles as an opportunity to appoint a more radical chief executive to one of the UK’s most important economic regulators.

It will also fuel speculation of a merger between mobile companies Vodafone UK and Three to encourage infrastructure investment.

According to government insiders, ministers regarded Mr Coscelli as an impediment to post-Brexit economic reforms and saw him as a hurdle to breaking with EU competition policy.

During his tenure, Mr Coscelli oversaw a raft of high-profile aborted and successful mergers of major British companies.

In 2019, the regulator blocked the merger of Sainsbury’s with rival Asda after concluding that it would lead to higher prices for consumers.

More recently, it ordered JD Sports to sell Footasylum and for Facebook to split from Giphy. It also previously blocked a merger between O2 and Three, and advised that Fox’s takeover of Sky could act against the public interest.

Lord Tyrie, the former CMA chairman who quit in 2020, said: “Andrea has done a great job in binding together the very different cultures of the CMA’s predecessor bodies. The CMA now faces a new set of challenges for which it will need to reboot itself.

“Improvements in productivity, competition and competitiveness are badly needed if higher economic performance is to be entrenched. The CMA will have to act more vigorously to tackle what appears to be a rise in [market concentration]. This goes hand in hand with rising consumer detriment.”