(ShareCast News) - The sale of Sainsbury's pharmacy business to Celesio has been delayed after the UK competition watchdog said it was launching a full investigation.The Competition and Markets Authority has referred Sainsbury's deal to outsource the management of its pharmacies to Celesio to a 'phase 2' investigation. Earlier this month, the CMA found 78 locations where it said could be affected by the deal and warned it would refer the merger for an in-depth probe unless Celesio offered acceptable undertakings to address the CMA's competition concerns.In its initial investigation, the CMA also said in several other places it had been unable to reach a positive conclusion on whether the merger gives rise to a realistic prospect of a substantial lessening of competition.But Celesio was unmoved and has not offered to make any concessions, leading the CMA to refer the deal to a full-scale probe with a deadline of 13 June 2016.Shares in Sainsbury's were down 0.6% to 264.8p by 1145 GMT on Tuesday.