Defender Jack Stephens has signed a two-year contract extension with Southampton and joined Middlesbrough on a season-long loan.
The 21-year-old has extended his St Mary's stay until 2019 and will spend the 2015-16 season with Boro in the Championship.
"The move to Middlesbrough is a fantastic opportunity for Jack on the back of his successful spell in League One with Swindon Town last year," Saints director of football Les Reed told the club website.
"Our decision to hand him a new, long-term contract is a show of the club's faith and trust in his development.
"Middlesbrough is a club with a good playing style and one likely to be challenging for promotion this season – an experience that Jack will surely relish."
Stephens scored one goal in 40 appearances for Swindon last year, helping the Robins reach the League One playoff final where they were beaten 4-0 by Preston North End.
