McLaren retain Jenson Button as partner for returning Fernando Alonso in 2015

Alonso's arrival has long been expected, but the identity of his team-mate was less certain, with the squad having been debating for some time whether or not to go for Button's experience or Kevin Magnussen's future potential.

An announcement on Thursday, however, at the team's Woking base saw the Englishman kept on for what will be his 16th season at the pinnacle of the sport.

Button comfortably outscored Magnussen in 2014, notching up 126 points to the rookie driver's 55.

Magnussen will though remain with McLaren as the team's test and reserve driver.

Meanwhile, Alonso's return comes despite the acrimonious split at the end of the 2007 season.

The Spaniard had become disillusioned at Ferrari, and with Honda returning as McLaren's new engine partner, was convinced that the move would give him his best chance of securing that sought after third title.

The announcement means that all the confirmed outfits for 2015 have now announced their driver's for next season.