Assistant Chief Constable Davy Beck says the public can expect to see increased vehicle checkpoints and patrols following a car bomb attack at the weekend.
Despite boasting squads that have included the likes of Lionel Messi, Neymar and Kylian Mbappe, it is the current Paris St-Germain side that is playing the club's most impressive football.
Barring an unlikely sequence of results, Old Trafford will host Champions League football again next season, but for those running the club, their most significant work is about to begin.