WHAT's lurking beneath the murky depths of one of the U.K.'s most important wildbird reserves?

Visitors to Martin Mere, the Wildfowl & Wetlands Trust in Burscough, near Ormskirk, have been experiencing some rather strange goings on lately.

And things got even stranger last night when several visitors witnessed a swan trying to flee the grasp of a giant underwater predator.

"Something is completely spooking them," comments Reserve Manager, Chris

Tomlinson. "On two occasions recently something in the water has caused the 1,500 plus wild wintering swans to completely disappear".

Centre Manager, Pat Wisniewski adds: "Whatever it was out there last night must have been pretty big to pull a swan back into the water, swans weigh up to 13 kilos".

Pat said: "This could be an extremely large pike, or a Wels Catfish, both conceivably could survive in the rather murky, de-oygenated water for years and grow to an extremely large size".

In fact, four years ago Pat spotted something that appeared to be the size of a small car circling just below the waterline.

One theory is that something may have made its way into the mere through its drainage system many years ago as a juvenile and remained there ever since having grown too large to escape.

Visitors to Martin Mere are asked to keep their eyes peeled for what just might be Lancashire's very own Loch Ness Monster!