FISHERMAN Len Smith is hoping to land a fortune after figuring out a use for a mysterious Viking artifact.

The 47-year-old believes the 1,000-year-old whalebone was used as an ancient hand-line for catching fish.

He is so confident his theory is no tall tale that he plans to patent the design to produce a hand-line which could revolutionise the sport.

Mr Smith, from York, said: "This tool works so much better than the H-shaped hand-lines you see people using today - you can actually cast off with this one."

The artifact was on display at the city's Yorkshire Museum during this year's Jorvik Viking Festival.

Puzzled staff asked the public for ideas to help solve the mystery as to what it may have been used for - which is when he put his own idea forward.

He then went back to the drawing board and came up with his own advanced interpretation.

He said: "When I saw it was made of whalebone, I immediately thought it was a tool used for fishing.

"I have designed one very similar made from solid oak, because it would be strong, robust and durable, and I find that it actually works extremely well."

The museum's keeper of archaeology, Elizabeth Hartley, said there had been many imaginative ideas as to its use, including a ceremonial axe and part of a weaving loom.

But she conceded that Mr Smith's concept was by far the most impressive.

She said: "He has helped us to look at the object in a way we had not looked at it before. We are now going to put his idea forward to specialists in Scandinavia.

"We will see if the Viking object has a modern-day equivalent over there, which may shed some light on its origin."