Former Manchester United defender Rio Ferdinand declares he was world's best centre back for four years and compared himself to rival stoppers

Rio Ferdinand believes he was the world's best centre back for four years during his time at Manchester United. 

The former England captain was asked by BT Sport presenter Jake Humphrey if he ever thought he was the best in the world. 

And Ferdinand declared he thought he was as good as the likes of John Terry and Sol Campbell during his heyday.