Arsenal have beaten north London rivals Tottenham to the signing of William Saliba in a deal reportedly worth around £27million that will see the teenager return to Saint-Etienne on loan.

French centre-back Saliba will head straight back to Stade Geoffroy-Guichard for the 2019-20 season after penning a “long-term” contract with the Gunners.

The 18-year-old becomes Unai Emery’s third signing of the close season following the capture of young Brazilian forward Gabriel Martinelli and Real Madrid’s Dani Ceballos.

Saliba is a considered a talented prospect but will have to bide his time for an opportunity at Emirates Stadium.

He made 16 appearances in Ligue 1 last term, with Tottenham also reportedly having made a late bid for the player.

Celtic left-back Kieran Tierney remains a target, with Arsenal reportedly having had bids for the 22-year-old rebuffed.