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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Sunny spells and scattered showers perhaps heavy at times.
Mostly dry at first with sunshine at times, although further scattered showers will spread in from the west during the day.
Most parts of the West Midlands will remain dry with some clearer spells developing later.