“Its skin was like a seal’s but it’s shape was completely abnormal – it’s not like any animal I’ve ever seen before.”

This is believed to be the eighth sighting of a long humpbacked creature – known by local residents as “Bownessie” – in the past last five years.

Mr Pickles’ companion Sarah Harrington, 23, said: “It was like an enormous snake.

“I only saw it for a few seconds but all I could think about was that I had to get off the lake.”

The pair were on the last day of a team building residential training course at Fallbarrow Hall, Bowness, Cumbria.

They said they had kayaked 300m out into the lake near Belle Isle when they spotted the beast to the south.

Mr Pickles’s picture perfectly matches the description of an earlier sighting from the shores of Wray Castle in 2006 by journalism lecturer Steve Burnip.

He said: “I’m really pleased that someone has finally got a really good picture of it.

“I know what I saw and it shocked me, it had three humps and it’s uncanny the likeness between this and what I saw five years ago.”

Photo expert David Farnell of Farnell’s photographic laboratory in Lancaster said: “It does look like a real photo but because it’s been taken on a phone the file size is too small to really tell whether it has been altered on Photoshop or not.”

Sceptics remain unconvinced that something so large could exist in the 11 mile long lake.

Dr Ian Winfield, a lake ecologist at the University of Lancaster, said: “It’s possible that it’s a catfish from Eastern Europe and people are misjudging the size but there is no known fish as large as the descriptions we’re hearing that could be living in Windermere.

“We run echo sounding surveys every month and have never found anything.”New