Britain's SBS - or Special Boat Service - was the world's first maritime special operations unit. Founded in the dark days of 1940, it started as a small and inexperienced outfit that leaned heavily on volunteers' raw courage and boyish enthusiasm. It went on to change the course of the Second World War - and has served as a model for special forces ever since.

The fledgling unit's first mission was a daring beach reconnaissance of Rhodes in the spring of 1941. Over the next four years, the SBS and its affiliates would carry out many more spectacular operations in the Mediterranean, the Atlantic, the Channel and the Far East. These missions - including Operation Frankton, the daredevil attempt by the 'Cockleshell Heroes' to paddle up the Garonne river and sink Axis ships in Bordeaux harbour - were some of the most audacious and legendary of the war.

Paddling flimsy canoes, and armed only with knives, pistols and a few sub-machine guns, this handful of brave and determined men operated deep behind enemy lines in the full knowledge that if caught they might be executed. Many were.

Yet their many improbable achievements - destroying enemy ships and infrastructure, landing secret agents, tying up enemy forces, spreading fear and uncertainty, and, most importantly, preparing the ground for D-Day - helped to make an Allied victory possible.