Duncan Castles confirms Man United have been scouting 21-year-old ‘for a long time’

Manchester United have been keeping tabs on Celtic defender Kieran Tierney

Manchester United manager Jose Mourinho Photo: Uefa handout

Manchester United have been monitoring Celtic defender Kieran Tierney over the past few seasons, Duncan Castles has confirmed.

The Scotland international was voted Celtic’s player of the year last season after Brendan Rodgers’ side won the Scottish Premier League title.

Jose Mourinho is in the market to sign a new left-back following Luke Shaw’s unconvincing performances in the Manchester United team.

Tierney is rated as one of Europe’s most promising full-backs and the Scotland international has Champions League experience under his belt.

Manchester United are also thought to be keen on a deal to sign Brazil international Alex Sandro from Serie A champions Juventus.

However, Tierney would be available in a more financially advantageous deal than Sandro given Juve’s lavish demands.

Sunday Times reporter Castles confirmed that Manchester United have been keeping tabs on Tierney.

“Celtic know Man United have been scouting Tierney for a long time and their admiration has only grown,” Castles told the Transfer Window podcast. “They are not sure that Man United will bid.”

Tierney has scored seven times in 132 games in all competitions for Celtic since making his debut in the 2014-15 season.

The promising left-back has won the SPL title three times, the Scottish Cup twice and the Scottish League Cup.

Manchester United have signed Fred, Diogo Dalot and Lee Grant in the summer transfer window so far following their second placed finish last term.

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