A minke whale stranded in the River Thames has been put down after it became "very distressed," a Chiswick RNLI spokeswoman said.
The whale was first spotted at Richmond Lock and Weir on Sunday May 9 before it swam upstream and became trapped against the riverbank near Teddington, south west London.
Rescuers monitored the creature but it became trapped against the riverbank near Teddington, south west London, and the London Fire Brigade, and the British Divers Marine Life Rescue, were drafted in.
The services worked together to free the whale, which was achieved on the morning of Monday May 10 by moving it to a "deeper part of the river."
Chiswick RNLI continued to monitor the whale but it was "displaying concerning behaviours," and experts believed "it may be unwell," a spokesman said.
Sadly, a vet was called to euthanise the create after it became "very distressed."
In a statement, Chiswick RNLI said: "Chiswick's RNLI crew were tasked by London Coastguard at 8pm on Sunday May 9 and worked with the fire rescue service, police and British Divers Marine Life Rescue to try to free the whale.
"Together they managed to free it and were taking it to a deeper part of the river when it swam away.
"The whale was displaying concerning behaviours and experts in attendance were concerned that it may be unwell."
RNLI volunteers had also noted the whale may have been underweight and had some injuries on its pectoral fins.
It had previously been reported the whale, which was between 3m (10ft) and 4m (13m) long, would likely not survive and make it back to sea.
Minke whales are usually found in the northern Atlantic and Pacific Oceans.
The whale’s death comes after two killer whales were spotted off the Cornish coast for the first time in 10 years on Wednesday, May 5.