Oldest submarine dive

Today, the Nautical Archaeology Society and the Tunbridge Wells Sub Aqua Club will be marking the anniversary of the loss of the Holland 5 submarine - the Royal Navy's oldest submarine wreck - with a dive 100 years to the day after its loss.

Hundreds of years of maritime activity, two World Wars and numerous seafaring accidents have seen the seas and shores around the south coast become steeped in legend and undiscovered pockets of history. One piece of naval history that remained undiscovered until 1995 was the Holland 5 submarine.

Lying, upright in 30 metres of water, the Holland 5 was one of the Royal Navy's first submarines accepted for service, alongside the Holland 1 now on display at the Royal Navy Submarine Museum in Gosport.

The Holland 5 was commissioned on the January 19 1903. However, the Holland series of submarines rapidly became obsolete and on the August 8 1912 she was being towed to Sheerness for decommissioning and sank in her current position off the coast of Eastbourne, six miles southeast of the Royal Sovereign Lighthouse.

There was no loss of life when the Holland 5 sank, just a loss of the most intact example of the Holland series of submarines.

The cause of the sinking was believed to be as a result of flooding through a torpedo hatch and she lay undiscovered for almost a century.

The wreck is protected and managed by English Heritage but the Nautical Archaeology Society and the Tunbridge Wells Sub Aqua Club have a special licence to dive the wreck for monitoring and research purposes.

Already on board for today's visit are representatives from English Heritage and the Royal Navy Submarine Museum.

The dives planned will continue to monitor the condition of the wreck, which is almost completely intact on the seabed but is occasionally subjected to damage by trawling activity.

In 2011 it was added to the Heritage at Risk Register, collated by English Heritage.

"We have been diving on the Holland 5 since 2005 and have spent a lot of time clearing the wreck of netting and fishing lines," said Mark Beattie-Edwards, NAS Programme Director and a current licensee of the Holland 5 wreck.

"This month we have been undertaking an investigation into the sinking as part of an episode of Time Team and hope that we can raise awareness to the threat to our underwater cultural heritage by not respecting it."