They were periodically embodied for home defence and internal security, including the Spanish Armada campaign in 1588, and saw active service during the Wars of the Three Kingdoms.

The coastal towns of Kent forming part of the Cinque Ports also had a legal obligation to supply ships, seamen and marines for the Royal Navy.

Two thousand of the Kent trained men were sent to join the main Royal army at St James's Palace in London, and 4000 foot and 725 horse were to be sent into the neighbouring county of Sussex if the Spanish landed there.

In February 1639 the Lord Lieutenant of Kent, the Earl of Pembroke, was ordered to select 1200 of the Trained Bands for Sir Thomas Morton's Regiment of Foot in the Marquess of Hamilton's army, which was to make an amphibious landing in Scotland.

On 16 April the men embarked on a convoy of small ships to Harwich, where they were joined by the Essex Trained Bands contingent for Morton's Regiment.

[22][23] Kent's quota for the 1640 campaign was 700, not including the Cinque Ports' 300, to be sent by sea to join the army assembling on the Scottish border.

Kent however was notably uncooperative and Sir Humfrey Tufton could not persuade the yeomen and farmers amongst the trained bandsmen to go to Scotland, and the numbers had to be made up with pressed men.

[19][24] Control of the trained bands was one of the major points of dispute between Charles I and Parliament that led to the English Civil War.

However, with a few exceptions neither side made much use of the trained bands during the war beyond securing the county armouries for their own full-time troops, many of whom were recruited from their ranks.

[54] Kent was well within the area controlled by Parliament, but in the summer of 1643 there was a rising in the county – nominally Royalist, but including local troublemakers.

For a week from 18 July armed bands took control of Tonbridge and Sevenoaks, plundering the houses of rich Parliamentarians and taking the militia weapons stored at them.

Regular and LTB regiments under Maj-Gen Richard Browne were sent down from London to support the Kentish forces, and the insurgents retreated to Tonbridge.

The London troops left on 29 July, when 'Hercules Holliland'[a] was appointed Sergeant Major General of the Trained Bands in Kent.

The Sutton at Hone Volunteers marched with regiments of the LTBs in Parliament's expedition to relieve the Siege of Gloucester, which was achieved on 8 September 1643.

[37] However, the trial of those arrested led to further protests in May 1648, which former Royalist officers turned into an organised revolt, sparking off the Second English Civil War.

[39] Sir Thomas Fairfax led the New Model Army from London into Kent and defeated the main Royalist concentration at the Battle of Maidstone on 1 June.

Fairfax sent detachments to reduce Canterbury (where the Royalists surrendered without a fight), to recover Deal, Walmer and Sandown Castles, and to relieve Dover.

[85][86] Large numbers of Trained Band units were called out across England in 1650 during the Scottish invasion of the Third English Civil War, including those of Kent.

[87] After the 1660 Stuart Restoration, the 1661 Militia Act re-established the local trained bands, but placed them under the Lord Lieutenant of Kent, who was directly appointed by the king, with the men selected by ballot.

[25][88][89][90] The Kent Militia did duty to defend against threatened Dutch and French invasions, and helped to fight the Great Fire of London.