Militia
These were formed into trained band regiments, particularly in the City of London, where the Artillery Ground was used for training. The trained bands performed an important role in the English Civil War on the side of parliament, in marching to raise the siege of Gloucester (5 September 1643). Except for the London trained bands, both sides in the Civil War made little use of the militia, preferring to recruit their armies by other means.

Militia in the English Empire and the British Empire: As successful English settlement of North America began to take place in 1607 in the face of the hostile intentions of the powerful Spanish, and of the native populations, it became immediately necessary to raise militia amongst the settlers. The militia in Jamestown saw constant action against the Powhatan Federation and other native polities. In the Virginia Company's other outpost, Bermuda, fortification began immediately in 1612. A Spanish attack in 1614 was repulsed by two shots fired from the incomplete Castle Islands Fortifications manned by Bermudian Militiamen. In the Nineteenth century, Fortress Bermuda would become Britain's Gibraltar of the West, heavily fortified by a Regular Army garrison to protect the Royal Navy's headquarters and dockyard in the Western Atlantic.
In the 17th Century, however, Bermuda's defence was left entirely in the hands of the Militia. In addition to requiring all male civilians to train and serve in the militia of their Parish, the Bermudian Militia included a standing body of trained artillerymen to garrison the numerous fortifications which ringed New London (St. George's). This standing body was created by recruiting volunteers, and by sentencing criminals to serve as punishment. The Bermudian militiamen were called out on numerous occasions of war, and, on one notable occasion, to quell rioting privateers. The 1707 Acts of Union made Bermudian and other English militiamen British. The Militia in Bermuda came to include a Troop of Horse (mounted infantry) and served alongside volunteers and (from 1701) a small body of regulars. The Militia faded away after the American War of 1812 when the Parliament of Bermuda declined to renew the Militia Act. This resulted from the build-up of the regular army Bermuda Garrison along with Bermuda's development as the headquarters and dockyard of the North America and West Indies Station of the Royal Navy, which made the militia seem excess to need. Vast sums of the Imperial defence expenditure were lavished on fortifying Bermuda during the Nineteenth Century and the British Government cajoled, implored, begged, and threatened the colonial legislature for 80 years before it raised a militia and volunteer units (in 1894 and 1894 respectively). Although the militia had historically been an infantry force, many units in Britain had been re-tasked as militia artillery from the 1850s onward due to the increased importance of the coastal artillery defences and the new militia unit in Bermuda followed suit. Titled the Bermuda Militia Artillery, it was badged and uniformed as part of the Royal Artillery, and tasked with the garrison artillery role, manning coastal batteries. As in Britain, recruitment was of volunteers who engaged for terms of service, whereas the Bermuda Volunteer Rifle Corps was organised on the same lines as volunteer rifle corps in Britain. Recruitment to the BVRC was restricted to whites, but the BMA recruited primarily coloured (those who were not entirely of European heritage) other ranks, though its officers were all white until 1953. Neither unit was reorganised in 1908 when the Militia, Volunteer Force and Yeomanry in Britain merged into the Territorial Force, but the BVRC was re-organised as a territorial in 1921 and the BMA in 1926. The BVRC name was not modified to Bermuda Rifles until 1951, however, and the Bermuda Militia Artillery (and from 1939 the Bermuda Militia Infantry) continued to be titled as militia until amalgamated with the Bermuda Rifles in 1965 to form the Bermuda Regiment.
In British India, a special class of militia was established in 1907. This took the form of the Frontier Corps, which consisted of locally recruited full-time auxiliaries under British officers. Their role combined the functions of tribal police and border guards deployed along the North-West Frontier. Regional units included the Zhob Militia, the Kurram Militia, and the Chagai Militia. After 1946 the Frontier Corps became part of the modern Pakistan Army.

Political issues: Until the Glorious Revolution in 1688 the Crown and Parliament were in strong disagreement. The English Civil War left a rather unusual military legacy. Both Whigs and Tories distrusted the creation of a large standing army not under civilian control. The former feared that it would be used as an instrument of royal tyranny. The latter had memories of the New Model Army and the anti-monarchical social and political revolution that it brought about. Both preferred a small standing army under civilian control for defensive deterrence and to prosecute foreign wars, a large navy as the first line of national defence, and a militia composed of their neighbours as additional defence and to preserve domestic order.
Consequently, the English Bill of Rights (1689) declared, amongst other things: "that the raising or keeping a standing army within the kingdom in time of peace, unless it be with consent of Parliament, is against law..." and "that the subjects which are Protestants may have arms for their defence suitable to their conditions and as allowed by law." This implies that they are fitted to serve in the militia, which was intended to serve as a counterweight to the standing army and preserve civil liberties against the use of the army by a tyrannical monarch or government.
The Crown still (in the British constitution) controls the use of the army. This ensures that officers and enlisted men swear an oath to a politically neutral head of state, and not to a politician. While the funding of the standing army subsists on annual financial votes by parliament, the Mutiny Act, superseded by the Army Act, and now the Armed Forces Act is also renewed on an annual basis by Parliament. If it lapses, the legal basis for enforcing discipline disappears, and soldiers lose their legal indemnity for acts committed under orders.
With the creation of the British Empire, militias were also raised in the colonies, where little support could be provided by regular forces. Overseas militias were first raised in Jamestown, Virginia, and in Bermuda, where the Bermuda Militia followed over the next two centuries a similar trajectory to that in Britain.

18th century and the Acts of Union: In 1707 the Acts of Union united the Kingdom of England with the Kingdom of Scotland. The Scottish navy was incorporated into the Royal Navy. The Scottish military (as opposed to naval) forces merged with the English, with pre-existing regular Scottish regiments maintaining their identities, though command of the new British Army was from England. How this affected militias either side of the border is unclear.

British Militia: The Militia Act 1757 created a more professional force. Better records were kept, and the men were selected by ballot to serve for longer periods; specific provision was made for members of the Religious Society of Friends, Quakers, to be exempted, as conscientious objectors, from compulsory enlistment in the militia. Proper uniforms and better weapons were provided, and the force was 'embodied' from time to time for training sessions.
The militia was widely embodied at various times during the French and Napoleonic Wars. It served at several vulnerable locations, and was particularly stationed on the South Coast and in Ireland. A number of camps were held at Brighton, where the militia regiments were reviewed by the Prince Regent. (This is the origin of the song "Brighton Camp".) The militia could not be compelled to serve overseas, but it was seen as a training reserve for the army, as bounties were offered to men who opted to 'exchange' from the militia to the regular army.

Irish militia: The Parliament of Ireland passed an act in 1715 raising regiments of militia in each county and county corporate. Membership was restricted to Protestants between the ages of 16 and 60. In 1793, during the Napoleonic Wars, the Irish militia were reorganised to form thirty-seven county and city regiments. While officers of the reorganised force were Protestant, membership of the other ranks was now made available to members of all denominations.

Scottish militia: In the late 17th century, numerous individuals in the Kingdom of Scotland (then in a personal union with the Kingdom of England) called for the resurrection of a Scottish militia, with the understated aim of protecting the rights of Scots in Great Britain. After Scotland became part of the Kingdom of Great Britain, the Militia Act 1757 did not apply there. The traditional Scottish militia system continued, with only certain settlements in Scotland playing host to a militia regiment. This was viewed with resentment among some in Scotland, and the Militia Club was formed to promote the raising of a Scottish militia. The Militia Club, along with several other Scottish gentlemen's clubs became the crucible of the Scottish Enlightenment. The Militia Act 1797 empowered Scottish Lord Lieutenants to raise and command militia regiments in each of the "Counties, Stewartries, Cities, and Places" under their jurisdiction.