Amazon Inc. and Microsoft Corp.’s UK cloud service offerings are facing closer scrutiny in the UK as the watchdog said it had concerns over their market dominance.

The UK antitrust regulator has singled out Microsoft for using its dominance in software to stifle rivals in the £9bn UK cloud services market, as the watchdog warned competition “is not working”. An independent panel acting for the Competition and Markets Authority said on Tuesday that a lack of competition in cloud services was “likely to be leading to higher costs,