Manchester United goalkeeper David de Gea was left furious on Monday afternoon after he was forced to undergo two hours of random drug testing instead of joining his team-mates on their annual Christmas visit to a local hospital.

It is a tradition for United's stars to turn out at the Manchester Royal Children's Hospital to bring some Christmas cheer to young patients and a leading cast of players were once again present on Monday.

Ander Herrera, Juan Mata, Memphis Depay, Jesse Lingard, Morgan Schneiderlin, Anthony Martial, Matteo Darmian, Andreas Pereira and Sergio Romero were pictured in attendance to lift the spirits of their young supporters.

Manchester United's Ander Herrera and Juan Mata and meet Amelie, 10, with sister Fleur, 12, from Salford

Herrera holds Benjamin, 1, as part of the club's Christmas visit to Royal Manchester Children's Hospital

Herrera and Mata pose with baby Elsie, 39 weeks old, with brother Hayden, 4, and father, Darren

Spanish midfield duo Mata and Herrera met 3-year-old Hanna and gave her a present on Monday

Memphis Depay (left) and Jesse Lingard (right) smile as they visit Daniel, 11, from Preston

Dutch 21-year-old winger Depay and 23-year-old English star Lingard meet Millie May, 23 months, from Irlam

Depay and Lingard pose with 11-year-old David from Cork after giving the youngster his festive gift

Morgan Schneiderlin (left) and Anthony Martial (centre) meet Thomas, 18, from Altrincham

Goalkeeper David de Gea played as United were beaten 2-1 by Norwich City at home on Saturday afternoon

However, while his team-mates were spending time with the children and handing out Christmas presents, De Gea was instead locked into the United training ground for several hours - much longer than expected - while the football anti-doping agency carried out their tests at Carrington.

The agency did not provide prior notice and sources close to De Gea told Sportsmail that he was 'angry' to have missed one of the only days of the year where United stars are able to actively engage with their supporters.

De Gea is believed to be the only United player who was selected to take part in the two hours of testing, after which it became too late to accompany his colleagues at the hospital.

The Spanish goalkeeper, who came close to signing for Real Madrid in August before signing a new long-term contract at Old Trafford, remains a hugely popular figure with the United support.

He has been a shining light in an underwhelming United team once again this season, and last week admitted that he felt he was in the best form of his career.

'I feel really good right now,' he told United Review.

'I'm probably in the best physical shape of my career. Let's hope that there is still a lot ahead of me to achieve and that I can continue to improve in order to reach my highest possible level of performance.'

Met some great fans today on the @MU_Foundation Christmas visits. Always a special afternoon #MUFC pic.twitter.com/hmeiNekRwX — Wayne Rooney (@WayneRooney) December 21, 2015

De Gea was left furious on Monday afternoon after he was forced to undergo two hours of random drug tests

France internationals Schneiderlin, 26, and Martial, 20, meet Kaden, 13, from Salford

Schneiderlin and Martial get to know Alfie, 8, from Morecambe, who sported a United drawstring bag

Schneiderlin, Martial and Italian right back Matteo Darmian (right) pose with Luke, 10, from Preston

Darmian meets Ibrahim, 3, after United's 2-1 defeat to Norwich City at Old Trafford on Saturday

Brazilian youngster Andreas Pereira and Argentine stopper Sergio Romero meet Umar, 12, from Rochdale

Pereira and Romero pose with hospital staff at Royal Manchester Children's Hospital on December 21

Louis van Gaal's United side have failed to win any of their last six games during a rocky period for the club