British armoured trains often fell under the control of the Royal Navy, largely because they were built with naval materials and at naval initiative.

The 19th Century Royal Navy had a long tradition of forming 'naval brigades' to support the Army. These brigades, formed from the ship's marine detachments as well as armed sailors, provided amphibious expertise and extra manpower. They also provided heavy artillery for troops ashore; ships carried guns that were much heavier than those used by the Royal Artillery. Naval brigades were generally more readily available than extra troops, especially during Britain's colonial wars of the 19th Century, as there would always be a few warships available no matter wherever in the world a crisis occurred. RN sailors and officers were trained in operations ashore, including frequent rifle drills and tactics. It was these naval brigades that would pioneer British use of armoured trains.

In 1882, the Ottoman possession of Egypt rebelled, seeking to overthrow Turkish rule and establish an independent Egyptian nation. The British and French dispatched naval squadrons to Alexandria to protect their commercial interests there (and to extend their influence over Egypt). At Alexandria, the British commander, Admiral Seymour, felt threatened by Egyptian work on the forts protecting the harbour. He issued an ultimatum, instructing the Egyptians to surrender the forts within 24 hours, or he would open fire; meanwhile, the French departed. When the ultimatum ran out, Seymour opened fire, bombarding the forts into ruins. The Egyptian troops garrisoning the city withdrew, and Seymour landed a naval brigade to take control of it. They would later be reinforced by army troops, sent from Cyprus roughly a month after the landing. The naval brigade would construct Britain's first armoured train. The train is commonly attributed to Jacky Fisher, captain of HMS Inflexible and commander of the naval brigade (later First Sea Lord and a significant naval reformer), but there was also input from Captain Arthur Wilson of HMS Hecla. The train was manned by men from Hecla and armed with a 40pdr Armstrong gun and two machine guns. It was used to patrol the right (eastern) flank of the British defensive position, and to probe Egyptian defenses on the route to Cairo.

A month later, with it clear that an advance out of Alexandria would be impossible, a larger British force landed at Ismailia. Here, a second armoured train would be constructed by the crew of HMS Penelope, though it was manned by Royal Marines. This train would see more combat than Hecla's train. It provided some artillery support during the battle at Kassassin, where its commander was killed. After this, it supported the naval brigade at the Battle of Tel-El-Kebir, the final battle of the war.

The armoured trains of the Boer War often used naval materials in their construction. Naval guns were often mounted. Most of the trains in service at the start of the war were armed only with machine guns, and the first to receive artillery was one armed with four 12pdr naval guns at Simonstown. Later trains would mount 6in or 9.2in naval guns, as well as smaller guns on naval mountings. Naval equipment would also be used to armour the trains. Usually, this took the form of steel plate from naval stores, but in one case, thick naval rope was used to protect a locomotive, which soon gained the nickname 'Hairy Mary'. While the Navy provided much of the equipment, the trains were largely under the control of the Army. The trains were manned by soldiers, not sailors, and they were under the responsibility of the Army's Railways Director, Major Girouard. The most famous train of the war, the one Winston Churchill was travelling aboard when he was captured on the 15th November 1899, was operated by the 2nd Royal Dublin Fusiliers.

The First World War saw the RN return to commanding armoured trains. As German troops advanced through Belgium, they cut off the port city of Antwerp. As a German squadron based in Antwerp could threaten the important shipping lanes running into London, Winston Churchill (First Lord of the Admiralty) pressured the Admiralty into sending a large amount of aid to the Belgian troops defending the city. This started with naval guns, originally intended to bolster the forts around Antwerp. The Belgians had been seeing success with lightly armed trains, and decided instead to fit them to three armoured trains. These started with combined Anglo-Belgian crews - seven British gunners, seventy Belgian troops and volunteers from the Belgian railways to run the engines. After the Royal Naval Division arrived to defend Antwerp, the trains were handed over to British control and two were given British crews. They were named Churchill and Jellicoe; the third train, Deguise, would retain its original crew. Oddly, the trains came under the auspices of the Royal Naval Air Service, the navy's air force. As I've described previously, the RNAS had the most experience with armoured vehicles in the British military, and was responsible for scouting and patrolling for the Royal Naval Division. This meant that it made sense for the armoured trains, intended for this role, to be put under RNAS control. The trains provided counter-battery fire during the siege of Antwerp, before covering the withdrawal of Allied troops as the city fell. After this, they provided supporting fire during the First Battle of Ypres. During this time, three more trains (Sinclair, Singer and Sueter) were constructed, though these seem to be used more for mobile radio communications rather than as true armoured trains. Moving into 1915, as the front lines calcified, the trains became less useful. Without a clear role, and without Churchill's enthusastic support, the trains were removed from British service and handed back to the Belgians. The RN would operate another armoured train during the war, during the invasion of German South-West Africa (now Namibia). The train was armed with 6in and 4.7in guns taken from British warships, and was used to patrol the railways linking Namibia to South Africa against German guerilla attacks.

During the Allied intervention in Russia during the Russian Civil War, the RN would operate two armoured trains. The first was improvised to protect the railway link between the ports of Murmansk and Arkhangelsk. There are differing descriptions of it - Brown's The Royal Navy's Air Service in the Great War states that it was armed with 4in naval guns, while Malmassari's Armoured Trains more plausibly indicates that it was armed with a 4.5in howitzer, a 75mm field gun and a naval 6pdr gun. The other armoured train operated on the Trans-Siberian railway. It was manned by the Royal Marines, and armed with a 6in gun and four 12pdrs from the cruiser Suffolk. Both of these were local improvisations, using naval armaments and expertise because they were what was available.

The armoured trains of the Russian Civil War would be the Navy's last. While it did provide guns and gunners to a few of the Army's trains, it would command no others. During the invasion scare of 1940, a naval armoured train was mooted, but it never got off the drawing board; meanwhile, the Army would operate twelve armoured trains, plus a thirteenth on the Romney, Hythe and Dymchurch Light Railway. In the interwar period, there was little need for the sort of colonial policing and expansion that had seen the naval brigades come to prominence in the 19th Century. Instead, the British military was more concerned with suppressing insurgencies in colonies it already controlled. These tasks fell under the auspices of the Army. While armoured trains were used, these were constructed or improvised by the local Army units, without the need for naval assistance.