COUNCIL bosses are investigating a security breach after a protester climbed on to the roof of Bolton Town Hall.
A bedsheet, emblazoned with the words “Bolton MBC Labour Are Corrupt”.
Painted in red and black, was draped over the balcony of the grade-II listed building on Friday, by the flagpole.
It was in place for an hour in the afternoon before security guards took it down, during which time it was mostly unreadable because it was folded over itself.
A council worker said that high-level management had been reviewing CCTV footage from Friday to identify the culprit.
The roof is inaccessible to the public and can only be reached by a locked door.
Building work is being carried out on the third floor of the town hall and is closed to the public.
It is understood that when security staff reviewed the CCTV footage, they spotted an unknown man carrying a backpack on to the roof after he had snuck in with construction workers.
Bolton Council is spending up to £3.5 million refurbishing the town hall.
It will involve creating large open plan offices, doubling the number of staff able to work in the building.
Once complete, the council says it will be able to save £1 million by disposing of other buildings.
A council spokesman said the banner had been taken down and officials were investigating the incident.