Although the War Office took over from local officials the funding and operational control of auxiliary forces in the British Isles from 1871 onwards, the trend of Imperial defence policy during the course of the 19th century was to remove regular units of the British Army from colonial garrison duty wherever strategic concerns did not require their retention (this included disbanding colonial regular units of the British Army, other than the
West India Regiment and the local-service sub-unit of the
Royal Artillery that would ultimately be titled the
Royal Malta Artillery, though others would later be raised), with local governments expected to organise and fund auxiliary forces for local defence (although these forces would ultimately be controlled by the Imperial government via colonial Governors, most of whom were civilians, acting as military commanders-in-chief). The main exceptions were the four Imperial fortresses, which the regular army continued to garrison, and within which the part-time militia and volunteer units were funded as parts of the British Army and brigaded with regular units. The
1887 Colonial Conference sat in London from April 4 until May 9, 1887. At the conference, it was asserted that: on the America & West Indies Station, 1936-1939 Halifax and Bermuda controlled the transatlantic sea lanes between North America and Europe, and were placed to dominate the Atlantic seaboard of the United States (as demonstrated during the
American War of 1812, when the squadron of the Royal Navy's North America Station maintained a blockade of the Atlantic coast of the United States and launched the
Chesapeake Campaign from Bermuda, defeating American forces at
Bladensburg,
burning Washington, DC, and
raiding Alexandria, Virginia, before ultimately being
defeated at Baltimore and forced to withdraw back to Bermuda), as well as to control the western Atlantic Ocean from the Arctic to the West Indies. In 1828, Royal Navy Purser
Richard Cotter wrote of Bermuda: Gibraltar controlled passage between the Atlantic Ocean and the Mediterranean Sea, and Malta, aside from supporting operations in the Mediterranean and
Black Sea, served as a base for naval and military forces that would be able to deploy relatively quickly to the Indian and Pacific Oceans once the Suez Canal was completed in 1869. Halifax ceased to be an Imperial fortress in stages. With the 1867
confederation of the
Dominion of
Canada (under which all of the colonies of the British Empire's administrative region of
British North America, except Bermuda and
Newfoundland, were
"federally united into One Dominion under the Crown of the United Kingdom of Great Britain and Ireland, with a Constitution similar in Principle to that of the United Kingdom ..."), military defence of Canada would be transferred to the
militia of the dominion government, and the British Army withdrew most of its establishment from the continent, leaving small military garrisons to defend the
Royal Naval Dockyard at Halifax, Nova Scotia and the
Esquimalt Royal Navy Dockyard in
British Columbia. These garrisons were withdrawn along with the Royal Navy establishments when the two Canadian dockyards were closed in 1905, then sold to the government of the dominion. 1st Division (
HMS Dragon,
HMS Danae and
HMS Despatch) off
Admiralty House in 1931 as they depart their base at the
Royal Naval Dockyard in
Bermuda to exercise on the open North Atlantic When the
Panama Canal opened in 1914, Britain was able to rely on amity and common interests between herself and the United States during and after the First World War, to use Bermuda also as a base from which cruisers could patrol the Pacific coasts of North, Central, and South America (the first Bermuda-based ship to pass through the canal being
HMS Chatham in 1920). The perception that the only navies that could threaten British control of the sealanes or territory around the globe were all those of countries on the Atlantic or its connected seas had meant Imperial fortresses were only established in this region. This was despite the growth of the Pacific Ocean fleets of Russia and the United States of America during the 19th Century. Finally the rising power and increasing belligerence of the
Japanese empire after the
First World War (The
Imperial Japanese Navy was the third largest navy in the world by 1920, behind the Royal Navy and the United States Navy) would result in the construction of the
Singapore Naval Base, which was completed in 1938, less than four years before hostilities with Japan commenced during the
Second World War. The need to protect these bases of operation, as well as to prevent, via their captures, their becoming bases of similar utility to an enemy (with ownership of land by foreigners, at least in Bermuda, barred in order to deny a pretext for invasion), each was heavily defended, making
fortress an apt designation. "Fortress" was often included when giving the names of these colonies, e.g. "Fortress Bermuda". Bermuda, protected by an almost impassable barrier reef and unconnected to any continent, required the least defences, but was heavily garrisoned and armed with
coastal artillery batteries. Defence of Bermuda, and of the region, was greatly weakened by the economic austerity that followed the conclusion of the Napoleonic Wars and the American War of 1812, which resulted in drastic reductions to the regular forces and to Reserve Forces in the British Isles (Militia, Volunteer Force, and Fencibles), and in Bermuda (Militia and volunteer artillery), being allowed to lapse. Bermuda's garrison would slowly increase, with the threat of invasion by the United States during and after the
American Civil War resulting in further strengthening of the defences. Bermuda's importance to Imperial defence was only increasing, however. Halifax was much more vulnerable to attack than Bermuda, which might come over land or water from the United States, Gibraltar was vulnerable to overland attack by Spain (which remains anxious to recover it) and by Napoleonic France, and both Gibraltar and Malta were much more vulnerable to the navies of the Mediterranean (notably those of Spain, France, Italy, and the
Ottoman Empire), and were even more heavily defended. ==Naval and military establishments of the imperial fortresses==