Pozzi was selected to represent Great Britain at the 2012 World Indoor Championships in Istanbul, his first senior International representation. He was the only British male sprint hurdler selected. He surpassed expectations by winning his heat, beating Liu Xiang in the process, with a new personal best of 7.61s which also made him fastest qualifier. Pozzi continued to impress by finishing second in the semi-finals with another personal best of 7.56s making him the second fastest British 19-year-old ever, just 0.01s behind Colin Jackson's record. He finished 4th in the final with a time of 7.58s.