Royal Navy divers have gone back to basics as they step up security around key ports in Britain.

Experts from the Southern Diving Group (SDG), based in Portsmouth and Plymouth, have scoured the waters in vital ports and bases in the first stage of safeguarding Britain’s maritime infrastructure from the underwater threat.

Underwater explosives and limpet mines, among other weapons, are considered as potential threats to merchant and military shipping.

By searching ports and quays, diving teams are familiarising themselves with their layout so that in future it will be easier to spot anything out of the ordinary.

“We are upping the ante,” said SDG Commanding Officer Lt Cdr Kim Godfrey. “We are getting to know our yards very well.

“You will see a lot more of our divers in the yards. For us it’s going back to basics. It’s what we did 30 years ago.”

He added: “It is a way of getting to know our own backyards; learning what is down there.

“For the guys it means working to our limits, long hours and long days.

“Our big push this year is underwater protection of major, strategic ports.”

Teams of divers have already carried out inspections in London, Portsmouth and Southampton.

At the same time, SDG is taking up the mantle of finding the next generation of ship’s divers.

It is now the unit’s remit to test suitable candidates with a two-day course held once a month.

One problem ship’s divers face is that the role is secondary to a sailor’s primary function on board - a ship’s diver is not a full-time occupation.

Nevertheless, their tasks are important, including underwater security – searching for possible explosive devices – and minor husbandry relating to their ship.

Details from SDG on (military) 9375 65087.