Glen Nicolaides, from London Fire Brigade, told the BBC the whale had been moved to a more “stable” location where it would be assessed to determine the scale of its injuries and whether it could be released.
Earlier, a witness told the PA news agency that “quite the crowd” watched as the attempted rescue took place.
Jake Manketo, 20, from Richmond, said: “Everyone here is just hoping they get it out.
“We couldn’t believe our eyes when we first saw the poor fella, not every day something like this happens in Richmond.”
