The Competition and Markets Authority said its “strategic market status” investigations would assess “mobile ecosystems” that include operating systems, app stores and browsers.

Apple and Google said they would work alongside the CMA, insisting that they support choice in the market.

The regulator’s chief executive Sarah Cardell said “more competitive mobile ecosystems could foster new innovations and new opportunities across a range of services that millions of people use”.

The regulator added in a statement that it would reach decisions on its investigations by the end of October.

The CMA noted that “virtually all mobile devices sold in the UK are pre-installed with either” Apple’s iOS operating system or Google’s Android.

In addition, their “app stores and browsers have either exclusive or leading positions on their platforms compared to alternative products and services”.

“This means Apple and Google are also able to exert considerable influence over much of the content, services and technological development provided on a mobile device,” it said.

The CMA announcement comes after it launched last week an investigation into Google’s dominant position in the search engine market and its impacts on consumers and businesses.

Britain’s Labour government this week appointed a former top executive at online titan Amazon to be the CMA’s interim chair, hoping the appointment will help drive economic growth.

While competition watchdogs around the world are heavily focused on probing technology giants, the UK government believes too much regulation is hampering economic expansion.

The appointment of Doug Gurr, former country manager of Amazon UK and president of Amazon China, to steer the CMA comes after his predecessor, Marcus Bokkerink, was reportedly ousted for not focussing enough on growth.

‘Work constructively’

Google said it would “work constructively” with the CMA over its latest investigation.

The company will also “pursue outcomes that avoid stifling choice and opportunity for consumers and businesses, and avoid exposing users to new security and privacy risks”, said Oliver Bethell, senior Google director for competition.

“In doing so, we will underline our commitment to a pro-innovation, evidence-based regulatory regime that enables continued investment and UK growth,” he said.

Apple said it “believes in thriving and dynamic markets where innovation can flourish”.

It added in a statement Thursday that “In the UK alone, the iOS app economy supports hundreds of thousands of jobs and makes it possible for developers big and small to reach users on a trusted platform.”

“We will continue to engage constructively with the CMA as their work on this matter progresses.”

The CMA noted that 94 percent of people in Britain over 16 years old, or about 56 million consumers, have access to a smartphone on which they spend an average of three hours per day.

“Almost 15,000 businesses are involved in the development of apps used on mobile devices in the UK, and the total UK revenue for app development is estimated to be around £28 billion ($35 billion),” the regulator said.

The Labour government, led by Prime Minister Keir Starmer, has struggled to boost the economy since coming to power in July.

The latest official data showed Britain’s gross domestic product rebounded less than expected in November at just 0.1 percent.

An inaugural budget from finance minister Rachel Reeves in October included tax rises for businesses, a decision some analysts see as a cause of Britain’s stalled economy.