The novelty of a whale wallowing in the River Thames soon gave way to concern for the stranded creature's safety.
Rescuers were finally able to load the whale on to a barge in the hope of taking it out to sea.
For many it was distressing that the experts seemed to do so little to help for so long.
But staying back was the best way to avoid causing it further distress, said Mark Stevens, of the British Divers Marine Life Rescue.
The River Thames is a noisier environment than a whale is used to as it is more typically found in open water.
Rescuers try to calm the whale
These creatures navigate by sound, and adding to the noise pollution by clogging the river with motorboats would have done more harm than good.
"Whales live in a world of sound, just as we live in a world of colour. The high-pitched sound of boat propellers could disorientate it further."
Thus the Port of London Authority, which controls the river, warned sight-seeing boats and news helicopters to keep clear as the whale cruised near Albert Bridge, which spans the river between Battersea and Chelsea, and later during the rescue attempt.
MISERY LOVES COMPANY?
Keeping the whale company would have been not only unnecessary but foolhardy as even a juvenile bottle-nose whale - as this one is thought to be - weighs at least two tonnes.
Spectators were warned against going into the river or throwing anything at the whale, and on Saturday morning three canoeists who tried to get a closer look were told to keep back for their own safety.
Rescuers waited for low-tide to intervene as it would be next to impossible to help a whale swimming in deep water. Not only could it get away, rescuers would be at risk of injury from just a flick of its powerful tail, said Mr Stevens. And the murky waters of the Thames made visibility underwater limited.
With the whale stranded in shallow water as the tide dropped, rescuers stepped in with inflatable booms, a harness and a giant floating crane. The whale was then kept wet while specialist vets, including Paul Jepson, of the Zoological Society of London, assessed its condition.
PLAY IT WHALE MUSIC?
Although this technique has been used with some success to lure beached whales back out to sea, it would have been unlikely to work in this case, Mr Stevens said.
"First, out of all the hundreds of types of whale we would have to get hold of a recording of a northern bottle-nosed whale song. Even then, it may not have much effect because the whale is stressed and there's a lot of background noise."
Trying to feed the whale would have been a waste of time, said Peter Evans, of the charity Sea Watch.
Keep clear, experts warn
"The whale is unlikely to be starving; it can survive without squid, its principal food source, for days thanks to its thick blubber layers."
Nor would it have been tempted by dead bait - vast quantities of live squid would have to found to lay a trail, especially as the whale went so far upstream in the narrow and winding River Thames.
Despite the seeming inactivity, rescuers were poised and ready from Friday. For the main danger would be injuries from the riverbed - the main cause of death among beached whales was damage done to the lungs and chest cavity.
Adult length: 7-10m (23-33ft)
Weight: 5.8-7.5 tonnes
Diet: Squid, fish
Habitat: Deep offshore waters
Range: Arctic and North Atlantic
Status: Lower risk, conservation dependent, protected since 1977
Distinctive feature: Bulbous forehead
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