Manchester United are launching a bid for Celtic fullback Kieran Tierney.

The Mirror says United are stepping up their efforts to sign Celtic's £25million rated defender Tierney this summer.

United boss Jose Mourinho sees Tierney as more versatile and better value for money than his other left-back target, Tottenham's Danny Rose.

Although Tierney signed a new six-year deal with Celtic last October, United are confident they could land the 20-year-old, who is likely to cost around half as much as Rose.

Tierney's ability to play anywhere across the back-four has made the defender a more attractive option for Mourinho, who has made a new left-back a priority this summer.