Incredible footage shows RNLI heroes rescuing a humpback whale - entangled in a lobster rope line.

The large mammal with a distinctive white tail, which had been seen locally in Cornwall months before and named Ivy, had sadly become trapped in lobster pot lines in Mount's Bay, West Cornwall.

Four rescuers from the RNLI managed to free the humpback whale after a rescue mission that took around 30 minutes on choppy seas.

The incident happened in Mount’s Bay, near the port of Newlyn, at 10am on Sunday, 31 March 31.

Isabelle O'Shea, who lives in Exeter, Devon, caught the moment the brave rescuers saved the struggling mammel and posted it across her channels.

She said: "Brave lifeboat volunteers rescue entangled humpback whale in Mount's Bay."

"Having driven to Cornwall for the weekend in the hope of seeing a humpback whale, I couldn’t have anticipated the drama that unfolded off Newlyn this afternoon. "

"A humpback whale, which has been identified as 'Ivy' and seen regularly off Porthleven recently, was spotted off Newlyn entangled in lobster pot lines."

"The local wildlife community was quick to act and British Divers Marine Life Rescue and the large whale disentanglement team were contacted. "

"With the risk to the whale and the shipping community, the Penlee inshore lifeboat crew were able to respond."

"In very rough conditions and in peril from the distressed whale, they were able to free it from the ropes and stayed with it as it gathered itself before going on its way. "

"Massive thanks and respect to the four crew members involved."

Isabelle, who shares her photography on Instagram and Facebook under the name 'The Dolphin Lady, said her and her husband had travelled all the way from Exeter that weekend to see humpback whales across Cornwall.

She explained: "Since the beginning of December there's been a lot of humpback whales in cornwall."

"We are a hour drive away, but its incredible to have these massive creatures on our coast."

Isabelle explained how many people were watching the highly emotional event unfold.

She explained: "I Cried when I took the video - the sea was so rough, I felt so scared for the crew on the boat because it’s so dangerous."

"The whale must have panicked and twirled on itself - she was entangled on one rope quite close to the shore."

"They managed to pull the rope and eventually used this hook - lent over and went under and then she was freed!"

"I thought she was going to kill the crew to be honest - humpback whales are roughly 18 metres long and very powerful!"

She explains how the four RNLI rescuers had to act in fear of the whale drowning or getting hit by the boats - as she was right in the middle of the channel.

Isabelle added: "It was really brave and was nice to watch in the end - as it was like the whale was getting her breath back and eventually she just flapped her tail as if to say thanks and dived!"

"I did want to see the whale but it was not quite what I had in mind!"