The Mediterranean, 1943... The HMS Rob Roy. A tiny machine, just 230 feet from stem to stern. In peacetime she would have trawled for cod. Now her catch is deadlier by far. Lieutenant-Commander Ian Ransome is a veteran of the treacherous front line of naval combat. Under sealed orders in the battle-tossed waters of the Mediterranean, he and his jack-tired crew face one final test of their courage....

In November 1941, Lt Ralph Trewin, DSC arrives at Singapore as second-in-command of HMS Porcupine. To the shell-shocked Trewin, the gun boat and her five elderly consorts symbolise the ignorance and blind optimism he finds in Singapore.

They were the men and women of the Royal Navy's Special Operations units. Carrying out lightning raids on hostile coasts, they became a navy within a navy - each handpicked for their individual skills, and all of them courageous. Against the mighty backdrop of World War II they performed their small but deadly operations - living often beyond hope, sometimes beyond mercy. This is the dramatic story of a handful of such people. The Volunteers.

There will be days when you wonder at and question some of the risks you had to take, the sacrifices you were forced to offer in the face of death. In Kiel Harbour, 1945, the war in Europe is at an end. But for Lieutenant Vere Marriott and the men of MGB 801, moored amid a nightmare of devastation, it is an uneasy, unsettled peace. New assignments ashore and afloat mean fresh tensions and conflicting emotions. For some, glory now takes second place to profit.

The year: 1943. Now there was to be no more retreat for Britain and her Allies. At last the war was to be carried into enemy territory. And from captured bases and makeshift harbours in North Africa, the Royal Navy's Special Force was to be the probe and the spearhead of the advance. To this unorthodox war came the corvette H. M. S. Thistle and her commanding officer, John Crispin.

It takes a special sort of courage to serve in midget submarines, and Lieutenant David Seaton, commanding officer of XE16, needs no reminding of the perils involved. The little X-craft with their four-man crews have been used against heavy enemy surface units and important harbour installations. But in 1944, with the Allies poised for an invasion through France, a new and more hazardous role is given to Seaton's flotilla.

The dramatic sequel to Badge of Glory, China 1900. When the Boxer Rebellion erupts into bloody war. The Royal Marines, true to their motto, are the first to land - and the last to leave. Again, a Blackwood is in command.

In 1941, when she was turned into an armed merchant cruiser, the SS Benbecula was already old. Yet even she was needed to protect the vital Atlantic sea lanes. Commander Lindsay, her new captain, had to work desperately to mould the ship’s company - raw recruits and old-timers - into a fighting force. And better than anyone, Lindsay knew this could be his last command, his last chance.

As the Second World War progresses, the destruction of Allied shipping mounts. Fighter pilot Tim Rowan is posted to an escort carrier to help guard the precious convoys. His adventures take him first to the Arctic and then the Indian Ocean.

Twenty-five years ago HMS Terrapin was part of a crack hunter/killer group in the Battle of the Atlantic. Now she is working out her last commission in the Gulf of Thailand. To Lieutenant-Commander Standish, the frigate seems to mark the end of his hopes of a career in the navy. Then a new captain arrives, a man driven by an old-fashioned, almost obsessive patriotism. And under his stubborn leadership, Standish and the crew discover a long-forgotten unity of purpose.

It was in 1943. On the Black Sea, the Russians were fighting a desperate battle to regain control. But the Russians’ one real weakness was on the water: whatever they did, the Germans did it better, and the daring hit-and-run tactics of the E-boats plagued them. At last the British agreed to send them a small flotilla of motor torpedo boats under the command of John Devane. Devane had been in the Navy since the outbreak of war.

Adriatic, 1940s... Curtis was the pro. He could steer a sub through a saloon and no one would notice. Duncan was the grumbler, more at home in the Aussie Outback than twenty fathoms under the Adriatic. Jervis was the spit-and-polish man, who knew the correct way to die. And George, the Cockney, was the toughest of them all. Four men in the Royal Navy’s smallest sub, preparing the way for history’s largest invasion.

The old submarine-chaser USS Hibiscus, re-fitting in a Hong Kong dockyard before being handed over to the Nationalist Chinese, is suddenly ordered to the desolate island group of Payenhau. For Captain Mark Gunnar - driven by the memory of his torture at the hands of the Viet Cong guerrillas - the new command is a chance to even the score against a ruthless, unrelenting enemy. But Payenhau is very different from his expectations....

HMS Temeraire: latest and most advanced of Britain's nuclear submarines. When Temraire's trials are cut short and she is ordered to the Far East to reinforce the fleet against a threat from Red China, her captain, David Jermain, knows that this is no routine exercise in flag-waving. And once in Asian waters, he and his submarine find themselves involved in a hidden, undeclared conflict beneath the sea.

HMS Wagtail is a river gunboat, a ship seemingly at the end of her unusual life, lying in a Hong Kong dockyard awaiting her last summons to the breakers' yard. Commander Justin Rolfe is also seemingly at the end of his useful naval life, an embittered man, brooding and angry from a court-martial verdict. Then the offshore island of Santu is threatened with invasion from the Chinese mainland.