LONDON, July 23 (Reuters) - Britain's competition

regulator said it plans to designate Apple ( AAPL ) and Google

with so-called strategic market status for their role

in mobile ecosystems, as it steps up scrutiny of what it has

described as their duopoly.

The plans announced on Wednesday follows findings by an

inquiry group at Britain's Competition and Markets Authority

(CMA) that a number of markets relating to mobile internet

browsers were not working well for consumers or businesses.

Apple's ( AAPL ) Safari and Google's Chrome dominate the mobile

browser market on iPhones and Android devices, respectively.

A strategic market status (SMS) designation allows the CMA

to impose interventions on a firm, such as requiring it to

adhere to specific behaviour so as not to undermine fair

competition.

In Apple ( AAPL ) and Google's cases, they could be forced to offer

more features and give users the option actively to choose their

preferred mobile browser, if recommendations from the CMA's

inquiry group are accepted.

Both Apple ( AAPL ) and Google pushed back against the CMA's

proposals, with Google calling the step "disappointing and

unwarranted."

"It is ... crucial that any new regulation is

evidence-based, proportionate and does not become a roadblock to

growth in the UK," Google's senior director for competition,

Oliver Bethell, said.

Apple ( AAPL ) said separately it was concerned that the new rules

being considered would undermine the privacy and security

protections expected by its users.