The year’s biggest-selling single to date, Pharrell Williams’ Happy, has now also been certified 3x platinum.
 
Happy first went on sale as the lead single from the soundtrack to Despicable Me 2, and has now sold just over 1.8m copies since its release in June 2013. 

The song went to No.1 in the Official Charts in the final week of 2013, and has gone on to spend a further three weeks in the top spot on separate occasions in ...