Freezing temperatures have not deterred dozens of divers from taking to the icy waters of a disused quarry which has claimed five lives in the past year.

Enthusiasts are continuing to use the Dorothea Quarry, in the Nantlle Valley, near Caernarfon, even though sub-zero temperatures can make swimming more dangerous.

The quarry is popular with diving enthusiasts

The pool is more than 300m deep in places has been the scene of many fatal accidents in recent years, but sub-aqua enthusiasts maintain that it is safe if treated with caution.

People travel from across Britain to spend a few hours exploring the depths of the quarry, which has a network of flooded tunnels and sheer drops, making it a unique inland diving experience.

It is considered on of the best freshwater diving lakes.

But what makes it so appealing is also what makes it dangerous for the inexperienced.

The hidden dangers have led some sub aqua organisations to abandon training dives, but experienced divers say it is safe as as long as users do not take risks.

'Beyond control'

"The type of people who are diving here and having accidents are diving to depths where there are not really a lot of chances," said diving instructor Simon Gardner.

"If something goes wrong, there are not a lot of ways out of it, and a lot of experienced divers have had accidents here which were beyond their control."

The quarry is privately-owned, which means those who use it are, technically, trespassing.

There are long-term plans to turn the quarry into a proper sub-aqua centre but, in the meantime, owner Glyn Small has warned divers to stay away.

Glyn Small: Appeal

After one of last year's tragedies, Mr Small said he had made repeated efforts to prevent thrill-seekers using the area, but all his attempts to block access had been ignored.

He said roads into the quarry had been closed off with 30 tonne boulders and huge trenches, but groups had still managed to get into the site.

The last person to die after diving at the quarry was 57-year-old garage owner Denis Dransfield from Oldham, Greater Manchester.

He failed to surface again during a diving expedition with a friend in November, and an inquest into his death has been opened and adjourned, pending a full hearing.