The UK Border Agency has confirmed the demonstrator on the roof of the Morton Hall centre in Swinderby near Lincoln is a detainee of the immigration centre.
"There is currently a peaceful protest ongoing at Morton Hall in which one detainee has scaled the roof.
"We are working with the Prison Service to resolve the situation."
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Monday will stay mostly cloudy with patchy rain at times.
A largely dry morning is forecast with limited sunshine.
The Riders of Shaam cycled from Leicester to Luxembourg in their latest challenge.