Chelsea have added their former left-back Ryan Bertrand to their list of summer transfer targets.

Antonio Conte wants to strengthen in both full-back positions and increase the competition for first-choice duo Marcos Alonso and Victor Moses. Conte is a huge admirer of Bertrand, who Chelsea sold to Southampton for only £10million in 2015.

Bertrand made just 27 League starts in nine years at Stamford Bridge having joined the academy from Gillingham.

The 27-year-old became the first player in Champions League history to make his debut in the final when Chelsea beat Bayern Munich in 2012.

But the arrival of Jose Mourinho as manager in 2013 ended his chances of regular first-team football. After being sent to Southampton, for what was his ninth loan spell from Chelsea, the deal was made permanent two years ago.

Bertrand has thrived at St Mary’s Stadium, becoming a regular member of the England squad and played at Euro 2016. Chelsea are keen to increase their home-grown quota.

Bertrand’s style of play as an attacking wingback is regarded as a perfect fit for Conte’s 3-4-3 formation.

Chelsea have shown no hesitation in buying back players they have sold in recent years. They re-signed both Nemanja Matic and David Luiz, while Everton striker Romelu Lukaku was subject of a bid during the last close season and is on their wish-list again for the end of this campaign. However, Chelsea face a tough task to prise Bertrand away from Southampton, who agreed a new five-year contract with him last summer and value the England international in excess of £25m.

Manchester City have also earmarked the former Gillingham trainee as a possible replacement for Gael Clichy.

Chelsea’s interest in Bertrand is further complicated by their desire to sign Southampton centre-half Virgil van Dijk. Standard Sport first revealed in December the Dutchman was a key target to strengthen central defence.

Liverpool and City have emerged as strong competition for the 25-year-old, who is struggling to play again this season after suffering an ankle injury in January. But Chelsea are confident they will win the race, despite Southampton insisting he is not for sale.

The Blues look certain to win the title this season and return to the Champions League as one of the eight seeds in pot one next term. They go into the home game against Crystal Palace tomorrow with a 10-point lead and are looking to secure their 14th consecutive win at Stamford Bridge in all competitions.

Eden Hazard (calf) and Thibaut Courtois (hip) are available for selection following minor injuries.