Bomb disposal experts are en-route to the scene to carry out investigations on the device.
The site has been partially evacuated and is expected to remain closed for at least a few hours, possibly for the remainder of the day.
UPDATE @ 12:30 – Lynnbottom remains closed to the public this afternoon. A Bomb Disposal team from Aldershot are expected to arrive at Downend shortly.
Local residents are being warned the site may remain closed for the remainder of today and should return tomorrow to dispose of their rubbish.
UPDATE @ 16:15 – The Lynnbottom civic amenity site has now reopened as normal after the suspected explosive device was found not to be dangerous by the Bomb Disposal team.