A 60ft (18m) whale that was discovered on a beach near Gerinish on South Uist on Tuesday has died.
Personnel at a nearby military rocket test range had been helping with efforts to lessen the distress of the dying animal.
The animal was thought to be a fin or a rare sei whale.
Defence contractor Qinetiq had agreed to shut access to the Hebrides Rocket Range until the whale died and security staff were patrolling the area.
British Divers Marine Life Rescue had sought help from the range in preventing people from gathering around the mammal.
Volunteers kept scavenging birds away from the whale before it died at about midday.
Charlie Phillips, a Whale and Dolphin Conservation Society field officer, described the whale as magnificent.
He said it may have got into difficulty after making a navigational mistake.
The Western Isles’ local authority, Comhairle nan Eilean Siar, has to make a decision on how to dispose of the dead whale.
Burying the animal at the beach is among plans being considered.
Mr Phillips said dealing with such a large carcase would be problematic.
He told BBC Scotland: “To try to dispose of an animal of that size is to create headaches basically because of the remoteness of the area.
“Sometimes the best thing to do is just to let nature take its course and it may wash out to sea again.
“If the local council can get in with machinery then the whale could be cut into pieces and possibly buried in landfill.”