The man on the roof of an immigration centre in Lincolnshire is a Chinese national. Staff at Morton Hall near Lincoln said he took to the top of the 30 foot high building at 1130 BST.
Trained staff are on the roof trying to negotiate with the man who is not said to be making demands. Emergency services were on scene, although several fire engines have now left.
Lincolnshire police were called to a similar incident yesterday when a different detainee also got onto the roof but that was quickly resolved.
More top news
Sunday will be windy with sunny spells at first.
Sunday's looking dry with sunny periods.
Paramedics had to take the boy to a hospital 18 miles away from his home following the closure of a local children's A&E.