At first each Commando consisted of ten Troops of fifty all ranks, but this organisation was found to be unwieldy and was subsequently altered, in early 1941, to six Troops of sixty-five. Later after the experiences in North Africa, where the Commandos had to hold ground 'in the line' but lacked the normal heavier infantry weapons, such as 3-inch mortars and Vickers' medium machine guns, a Support Troop - with these weapons- was introduced as was a MT (motor transport) Troop.

Whilst the first Commandos were being formed in the United Kingdom three Commandos were raised in the Middle East. Their organisation was different, and furthermore they recruited Palestinians - both Arab and Jews - and some Spanish veterans of the Civil War in addition to volunteers from the British Army stationed out there. They carried out some operations on the enemy-held coastline of North Africa and also on a target in the Mediterranean, but the outcomes were disappointing. However, from December 1940 No. 51 Commando was in action in Eritrea and Abyssinia, where they made a substantial contribution to the victory and liberation of those two Italian-held countries.

During the winter of 1940 the original concept of the Commandos being mainly employed on small scale 'tip and run' raids was being amended, in-as-much as the Director of Combined Operations, Admiral Sir Roger Keyes, with the approval and support of the Prime Minister, Churchill, began to visualise and plan for larger scale operations. Indeed it was to this end that the main training on the Isle of Arran was focussed and ultimately led to the dispatch of 'Layforce' to the Middle East.

Nevertheless, in spite of this development the original concept was maintained through the newly created Special Boat Section (SBS) and later the Small Scale Raiding Force (SSRF, later given the cover title of No. 62 Commando) and later still special small raiding parties for specific operations organised from personnel within a Commando.

The first big major raid was the combined Nos. 3 and 4 Commandos' raid on the Lofoten Islands on 4th March 1941. Taking the enemy completely by surprise, they struck a significant blow at the German war economy without loss to themselves. The tally of achievements was spectacular: the destruction of eleven fish oil factories processing cod oil for use in the manufacture of high explosives and other uses, together with the stock of oil, ten German and German-used ships were sunk, 215 German POW's were brought back, and equally important, although not reported at the time, a vital piece of equipment of the enemy 'Enigma' system for the researchers at Bletchley. This successful raid was also a welcome fillip to home morale at the time of the 'Blitz'.

Later Nos. 6 and 12 Commandos carried out further raids on Norway, but undoubtedly the most important and successful of these raids was the one on Vaagso on 27th December 1941. Supported by Hampden bombers and destroyers of the Royal Navy, the raiding force consisted of No. 3 plus a strong detachment from No. 2 Commando. After bitter fighting the Commandos destroyed the occupying German garrison, a coastal defence battery, several fish factories and 18,000 tons of enemy shipping. In addition, they brought back 98 prisoners plus valuable intelligence material. But this success came at a price - twenty Commandos killed and fifty-seven wounded in the fierce street fighting.

During February 1942 the first Royal Marine Commando was formed and originally called 'A' (RM) Commando, but later designated 'No. 40 RM Commando'. In October of that same year a second RM Commando, No. 41, was formed and by the time of D-Day 1944 there were eight RM Commandos in action alongside the Army Commandos.

Next came the greatest and most daring of the entire Commando raids, namely that on St. Nazaire on 28th March 1942. Under the command of Lieut. Colonel A. C. Newman, the raiding force consisted of all of No. 2 Commando plus demolition parties from Nos. 1, 3, 4, 5, 9 and 12 Commandos. Such was the importance and scale of this operation that whole books have been devoted to this single Commando raid.

Suffice it to add here that the main object of the raid was to put out of action the huge dry dock of St Nazaire, the largest in the world, and thus deny its use to the German navy in the crucial on-going Battle of the Atlantic. There were also additional objectives for the raiders that included the demolition of ancillary dockyard installations. In this action, which was successful, but costly in casualties, many brave deeds were carried out and heading the list of awards were two Victoria Crosses, one to Colonel Newman, the other, posthumously, to Sgt Durrant.

In May 1942 No. 5 Commando was in the vanguard of the invasion of Madagascar, an operation designed to thwart the enemy of the use of naval bases in the Indian Ocean and threatening our sea routes to the Far East. In a daring unsupported night landing, before the main assault, No. 5 neutralised two coastal batteries and captured some 300 prisoners with only light casualties to themselves. They followed up this success with actions that resulted in the capture of Diego Suarez and the seizure of both Tamatave and Tananrive, and finally a section of one Troop took part in an action mounted on requisitioned horses – reminiscent of the original Commandos of the Boer War, only then the Boer Commandos were fighting the British!

On 19th August 1942, two Army Commandos (Nos. 3 and 4) and one RM Commando (No. 40) took part in the controversial Dieppe Raid. In support of the main Canadian assault force, the tasks of Nos. 3 and 4 were to destroy the enemy coastal batteries covering the main landing beaches, whilst No. 40 had selected tasks in the port area and was to be responsible for reinforcements as required. In the pre-dawn run-in the landing craft of No. 3 were fired upon and scattered with the result that only two small parties managed to land, one was overwhelmed, but the other successfully engaged the Berneval battery for some hours before withdrawing.

On the other flank at Varengeville No. 4, under the command of Lord Lovat, carried out what was officially hailed as a 'classic operation of war' and completely destroyed the Hess Battery, successfully withdrawing and re-embarking with prisoners. In this action, Capt Pat Porteous of No. 4 won the Victoria Cross. Unfortunately, No. 40, when committed to their landing, under well-nigh impossible conditions, suffered severe casualties including the loss of their CO, Lieut. Col. Phillips. On the credit side of this overall costly operation, important lessons were learnt on the problems of large-scale combined operations and these were heeded and acted upon, particularly in the forward planning of Operation 'Overlord'.

In November 1942, Nos. 1 and 6 Commandos were in action in the Allied landings (operation 'Torch') in North Africa and subsequently served throughout the Tunisian campaign as part of the field force - a role they were neither armed nor equipped to carry out as they lacked not only transport but the normal heavy infantry weapons at that time.

Yet in spite of these shortcomings they fulfilled their commitments with distinction "from Fort Duperre in Algiers to the White House at Douar, the Green Gill near Sedjenane and the green plain of Goubellat" proving that, although originally organised and trained for seaborne raiding, they could turn their hands to anything asked of them. They returned to England as seasoned campaigners and each in possession of a letter of gratitude from General Eisenhower.

About this time, following the establishment of the Commando Basic Training Centre at Achnacarry, a further Commando training centre was set up at Braemar in the Cairngorm mountains of Scotland for the purpose of specialised training in mountain warfare, initially christened the Commando Mountain Warfare Training Centre (CMWTC). The instructors included a whole range of experienced mountaineers, including Major John Hunt, who later organised and led the first successful ascent of Mount Everest. Later CMWTC moved to St Ives in Cornwall to instruct two RM Commandos in cliff-climbing techniques for their proposed roles on D Day. Thereafter, the unit in addition to training cliff climbers also became the centre for the planning, training and experimenting for small boat and canoe raiding, and in this role several of the instructors took part in the operations at Walcheren and the crossing of the Rhine.

Back in the Mediterranean in July 1943, Nos. 3, 41(RM) and 43(RM) Commandos were in the forefront of the landings on Sicily - the stepping-stone to the invasion of Italy.

Thereafter, destroying an Italian battery covering the beaches at Cassibile, No. 3, at very short notice, followed up by capturing a vital bridge near Agnone.

A week before the subsequent invasion of Italy some 60 men of No. 3, under the command of Major Peter Young, landed on the 'toe' of the mainland to carry out raids and reconnoitre the coast defences prior to the main landings - these actions gave rise to the claim of this Commando that they were the first British troops to gain a foothold - and stay - on the continent of Europe after Dunkirk!

The next main action of the Commandos in Italy was at Salerno in September when Nos. 2 and 41 RM were engaged in bitter fighting suffering heavy casualties, but they did have notable successes. On one occasion, in a triumphant night attack, No. 2 took 136 German prisoners, which at the time was more than the whole Division, to which they were attached, had taken.