Britain's competition watchdog said on Thursday a UK telecom tower deal between Spain's Cellnex and Hong Kong-based CK Hutchison may raise "significant competition concerns" and risked higher mobile charges. The Competition and Markets Authority (CMA) said its investigation found that CK Hutchison should have sold its passive infrastructure assets, including towers and masts, to an alternative buyer rather than market leader Cellnex. Cellnex last year agreed to buy 24,600 telecom towers across Europe from CK Hutchison, which owns the Three mobile network in the UK, for 10 billion euros (US$11.31 billion).