The three-time champions are currently at the bottom of Premier Group A with time running out to try to finish in the top three and claim a place in next season’s British and Irish Cup. A Muir statement says: “Phil has worked alongside head coach Fergus Pringle for the past three seasons. “Through Phil’s and Fergus’s leadership Boroughmuir have helped develop a number of young players notably Harry Leonard and Robin Hislop who have moved up to the professional ranks. Also this season four of our under-20 players have won caps for Scotland. Phil thought it was the right time for a change and is seeking a new challenge.”