UK competition regulator probes Clayton $10 billion deal for Morrisons

(Adds dropped "s" to Morrisons in headline and first paragraph)

LONDON (Reuters) - Britain's competition regulator has formally opened an investigation into whether a takeover by U.S. private equity firm Clayton, Dubilier & Rice Holdings (CD&R) of Morrisons will reduce choice for supermarket customers in the country.

The Competition and Markets Authority said on Thursday it had launched a merger inquiry, inviting comments from interested parties and giving a deadline of March 24 for a preliminary decision.

CD&R, which has former Tesco boss Terry Leahy as a senior adviser, won an auction for Morrisons on Oct. 2, bidding a penny a share more than a consortium led by Softbank-owned Fortress Investment Group.

(This story refiles to add dropped "s" to Morrisons in headline and first paragraph).

(Reporting by Andres Gonzalez; Editing by Rachel Armstrong)