She reclaimed her crown from Bruce Springsteen's High Hopes, which fell a place to number two, having ended her two week run at number one last Sunday.
The quartet brothers Jack and Luke Patterson, Grace Chatto and Neil Amin Smith knocked Pharrell Williams' Happy off the summit to score their first chart topping single.
The track, featuring Jess Glynne, sold 163,000 copies over the last seven days, according to the Official Charts Company.
The quartet came together in 2009 while Jack, Grace and Neil were studying at the University of Cambridge.
Williams slipped into second place, while pop rockers The Vamps entered the chart at number three with Wild Heart, their second Omega Constellation Serial Number
The group, who have become known for their fusion of classical arrangements with house beats, made their singles chart debut last April with Omega Seamaster Watch Price
Mozart's House which Omega Watch Golden Temple peaked at number 17.
Girl group Neon Jungle's Braveheart came in at number four. Pitbull and Kesha's Timber slipped three places to number five.
Clean Bandit's Rather Be tops chart From Omega Seamaster Planet Ocean Chrono Orange
top five single.
British group Clean Bandit stormed to the top of the singles charts with their dance pop tune Rather Be.
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