Manchester United have suffered a second embarrassing security breach in the space of six months after two ticketless supporters hid overnight in the Old Trafford toilets in an effort to watch the Premier League match with Arsenal on Saturday 19 November. The pair, thought to be foreign students, were discovered during a sweep of the 75,635-seater stadium on the morning of the game after they had detached themselves from an official tour.

The Daily Mail understands the dedicated fans slept through temperatures of 2° on Friday in an effort to see the sold-out game, which finished 1-1 after Olivier Giroud's late header cancelled out Juan Mata's opener. Guides failed to spot that the touring group had become depleted, despite being urged to count customers in and out of the ground.

Police were called to the scene but decided against arresting the pair or pressing charges. United insist that although the supporters went undetected for a number of hours they were no risk to the public, having already had their bags and belongings checked with a scanner and metal detectors prior to entering the stadium.

A United statement read: "We realise people will go to any lengths to watch a game at Old Trafford but these people went too far. The fact that they and their belongings had been searched before entry means we are confident there was no risk to safety."

Old Trafford
United insist there was no risk to safety despite two fans staying the night at Old Trafford. Getty Images

The incident comes after the match with AFC Bournemouth on the final day of the 2015-16 season was abandoned after what later emerged as a dummy bomb device was found in a toilet before the game. United insisted after the episode that they carried out a full investigation and review of their security protocols, which are managed by external company Controlled Event Solutions, yet a second breach in the space of a number of months will undoubtedly raise concerns.

A source added: "You honestly could not make it up. The two have gone on the tour on the Friday and for some reason, they must not have counted the numbers in and out and they have stayed there overnight without anyone seeing them. After the Bournemouth fiasco they retrained all the staff and beefed up security and searches but then this happens."