(Recasts lead, adds background in paragraph 3, further details from ruling in paragraph 6-8, Apple in paragraph 13)
LONDON, Nov 30 (Reuters) - Britain's antitrust regulator can investigate Apple's mobile browser and cloud gaming services, London's Court of Appeal ruled on Thursday, overturning a lower court decision the watchdog said could undermine its power to launch probes.
The Competition and Markets Authority (CMA) opened a full investigation last year into the dominance of Apple and Alphabet Inc's Google in mobile browsers.
Apple argued that the CMA had "no power" to launch such an inquiry because it did so too late and that the probe should have been opened last June at the same time the CMA published a report on mobile ecosystems, which found Apple and Google had an "effective duopoly."
The Competition Appeal Tribunal (CAT) ruled in Apple's favour in March, but the Court of Appeal upheld the CMA's appeal on Thursday.
Judge Nicholas Green said in a written ruling that the CAT had "lost sight" of the CMA's role to "promote competition and protect consumers".
He also said there would be "serious consequences" for the CMA if the CAT's interpretation of the competition regulator's powers was correct.
"It would mean that the CMA had no jurisdiction, even some years later, to investigate concerns into the behaviour of an undertaking such as Apple or Google, even if such concerns were objectively justified," Green said.
"The CMA would be unable to impose a remedy designed to protect consumers in the public interest."
Sarah Cardell, chief executive of the CMA, welcomed the decision which she said "gives the CMA the backing it needs to protect consumers and promote competition in UK".
She said the CMA is ready to reopen the investigation "when the legal process is complete".
Apple has the right to seek permission to appeal the decision.
The CMA said its investigation is on hold pending any application for permission to appeal to the Supreme Court.
Apple did not immediately respond to a request for comment. (Reporting by Sam Tobin; editing by Michael Holden and Jane Merriman)