Adds Spirit Aerosystem's response in paragraph 3

June 30 (Reuters) - Britain's competition regulator said on Monday it has started a Phase 1 investigation into Boeing's BA.N planned acquisition of Spirit Aerosystems SPR.N, setting a deadline of August 28 for a decision.

The Competition and Markets Authority $(CMA)$ had said last week that it was weighing a probe into whether the deal could affect competition in the country or in other markets.

"The inquiry by the Competitions and Markets Authority was anticipated and is part of the normal process for acquisitions of this nature," Spirit spokesperson Joe Buccino said in a statement. Boeing did not immediately respond to a Reuters' request for comment.

Last year, Boeing agreed to buy back Spirit in a $4.7 billion all-stock deal to streamline its operations and improve quality control, years after spinning off the key supplier.

In April, Airbus AIR.PA finalized a deal to buy several of Spirit's facilities tied to its aircraft programs.

(Reporting by Unnamalai L and Shivansh Tiwary in Bengaluru; Editing by Shailesh Kuber and Tasim Zahid)

((Unnamalai.L@thomsonreuters.com;))