England defender Calum increased his Premier League experience away from north London last season with Middlesbrough.
Comfortable at right-back, centre back or in defensive midfield, he scored against Liverpool in our opening-day defeat before joining Boro for the rest of the season.
Calum went on to make 26 appearances in all competitions for the Teesside club, netting his only goal of the loan spell to help Middlesbrough secure a 2-2 draw against Pep Guardiola’s Manchester City, but was unable to help them avoid relegation to the Championship.
Born in Hampshire, Calum began his career at local club Southampton, making his senior debut in a Capital One Cup tie at Stevenage in 2012, aged just 17. He featured regularly for the Saints in 2013/14, making 21 Premier League appearances, predominantly as a right -ack, before joining us in the summer of 2014.
His impressive performances at the start of his Gunners career were rewarded with a first senior international cap, in a friendly against Norway in September 2014. He was still a teenager at the time.
Calum actually made his senior England debut before representing his country’s under-21s, who he helped to win the Toulon Tournament at the end of the 2015/16 season. It was the first time in 22 years that they had lifted the trophy and Calum’s calm and assured performances in central defence saw him named in the team of the tournament.