Manchester United have been left stunned after being quoted £50 million for Sean Longstaff by Newcastle United.

Longstaff has surprisingly emerged as a leading midfield target for Ole Gunnar Solskjaer but, despite having only made nine Premier League appearances for Newcastle, the Tyneside club have slapped a huge price tag on the 21 year-old’s head.

Ed Woodward, United’s executive vice-chairman, is understood to have contacted Lee Charnley, the Newcastle managing director, on Saturday to enquire about Longstaff only to be told he will cost £50m.

That figure is way over double what the Manchester club are prepared to pay for Longstaff, who value the youngster at between £18m and £20m.

Longstaff only made his Premier League debut last December but Newcastle are thought to be using the projected £50m fee that the Old Trafford outfit paid Crystal Palace for England Under-21 right back Aaron Wan-Bissaka as a benchmark.

United are believed to have been taken aback by Newcastle’s position. Longstaff is known to want to come to Old Trafford but Newcastle’s stance may force United to pursue alternative targets.