Career
Southampton
Turnbull started his career within the youth system at Swindon Town but later joined Southampton Academy. The young defender later turned professional with Southampton and signed a two-year extension in 2013. Loans to Swindon Town
On 8 August 2014, Turnbull joined Swindon Town on a season-long loan.
He made his debut on the opening day of Swindon"s 2014-2015 campaign at home to Scunthorpe United.
Turnbull scored his first ever goal for Swindon in a 3-3 home draw against Walsall in April. Foreign his impressive performances he was voted the Swindon Town Player of the Season
On 3 August 2015, Turnbull joined Swindon Town for another season long loan spell.
In the 2015-2016 he has played at left back on many occasions due to a centre half partnership formed between El-Abd and Branco. Turnbull has represented England at Under 19 and Under 20 level