Thames Estuary dead whale sparks coastguard alert 24 March 2013 Last updated at 11:42 A dead whale has been spotted in the Thames Estuary off the Isle of Grain in Kent, Thames coastguard has said. Coastguards are making plans for the carcass to be towed to Sheerness docks where Natural History Museum staff will examine it, a spokesman said. Navigation warnings were earlier being issued to vessels in the area to avoid the whale, thought to be a humpback, while coastguards kept a watch on it. But it later drifted closer to shore, coastguards said. It was spotted by the crew on a nearby tug and reported at about 07:00 GMT.