It's the size of a man's hand and it's growing in population.

The Fen Raft Spider was on the verge of extinction in the UK just 14 years ago, but now - thanks to the hard work of conservationists - up to 3,750 breeding females have been recorded at 12 sites in Norfolk alone. 

While this is undoubtedly a conservation success story, it has struck fear in the hearts of arachnophobes all over the country.

The Fen Raft Spider is roughly the size of an adult male's hand, and can spin webs as big as pizzas (25cm).

They are also semi-aquatic and can run across the water’s surface to capture their prey. 

Their diet includes other spiders, damselflies, dragonfly larvae and pond skaters, and they will even catch fish and tadpoles. 

Back in 2010, the spider was restricted to just three sites in the UK and only a handful of spiders remained. 

Efforts to improve the creatures habitat and damp weather in recent years are thought to have given the species a boost.

Whilst the species remains Vulnerable and listed as a Priority Species, the annual spider surveys take place in September and many people involved in their conservation hope it to be another successful breeding year.

The RSPB Mid Yare nature reserves is an organisation based in the Norfolk Broads, set up with the aim of protecting a mosaic of wetland habitats which are home to bitterns and other important species.

Site manager Tim Strudwick, told Mail Online that he was proud that the spider had recovered. 

"The Fen Raft Spider is one of the UK’s rarest invertebrates and we are proud of the role our reserves and teams have played in its recovery," he said.

"These spiders have an important role in maintaining the rich aquatic diversity found in the grazing ditches on our reserves. 

"The females are impressive in size, but also beautiful – they are truly special to see."

He added: "The spiders are only seen in the grazing marsh ditches and are fairly shy but are easier to see from June to September. 

"Walking along the meadow trail gives visitors at Strumpshaw Fen the best chance of sightings of the mature females and their glistening nursery webs, so now is the perfect time to make a trip to the reserve."

Despite the Fen Raft's bite being poisonous and painful, they are not considered dangerous and a nibble from one of them would only lead to minor pain and swelling.

If you think you have seen a Fen Raft Spider, submit your record to the National Spider Recording Scheme.