The corps was rapidly expanded or decreased in size as needs arose and played a key role in regulating the manpower requirements of the British Army.

The corps was organised into a number of independent companies that were garrisoned at key points in the country, freeing up units of the regular army for service overseas.

William III disbanded the corps shortly afterwards but it was reformed in 1690 to provide manpower for the ongoing War of the League of Augsburg.

In 1802 the corps was disbanded with able-bodied men being absorbed into the new Royal Garrison Battalions and ultimately into regular line infantry regiments.

[1]: 5  The corps's role was to provide garrisons to forts in the Great Britain, freeing up regular units of the British Army for service overseas.

[1]: 7 The corps played a vital role in regulating the manpower requirements of the British Army, increasing or decreasing in size as the need arose.

The examinations also acted as a means of reducing the number of fraudulent pension payments to deceased or able-bodied men and of keeping records updated.

[1]: 204 Owing to their disability and age many members of the corps spent as much time on the sick roll as they did on duty, one exception was the garrison on the Isles of Scilly which benefited from a warmer climate.

[1]: 200  Before becoming eligible to receive this the discharged man was subject to a medical examination, in the intervening period the hospital paid for their travel and lodgings.

[1]: 5  However in 1716 the Corps of Invalids was brought within the scope of the Mutiny Act, coming for the first time under the same disciplinary arrangements as the regular army.

Recruitment proved easier than anticipated and there was no difficulty in providing each company with a Captain, Lieutenant, Ensign, two Sergeants, three Corporals, two Drummers and 50 Privates.

The invalid companies do not seem to have opposed the invasion despite the fact that William's Dutch Guards marched straight past the gates of the Royal Hospital.

[2]: 282 Having been raised on the orders of James II the companies were suspected of being loyal to the deposed king and were disbanded by the new William III – though he allowed them to retain their army pensions.

[2]: 282  William instructed Lieutenant-General Thomas Tollemache to reinstate the corps in May 1690, forming a company of 2 drummers, 6 sergeants, 10 corporals and 100 privates to supplement the garrison at Windsor Castle.

The intention seems to have been to free up space at the Royal Hospital Chelsea for casualties from the War of the League of Augsburg and to absorb some of the soldiers from units disbanded following the Treaty of Ryswick.

[2]: 284 In February 1703, during the reign of Queen Anne, the Duke of Marlborough as Commander-in-Chief of the Forces was apparently responsible for reducing each company of the corps to a captain, lieutenant, ensign, 3 sergeants, 2 corporals, a drummer and 75 men.

In 1704 the corps provided a unit for garrison duty at Kensington Palace, releasing a detachment of 600 Foot Guards for service in Portugal during the War of the Spanish Succession.

The army found it difficult to find enough retired officers to fill the positions and some Chelsea Hospital staff had to be called upon to serve.

Three were posted to the Tower of London and four were sent to augment the garrison at Portsmouth which had been depleted by sickness and drafts for overseas service in the War of Spanish Succession.

The latter four companies were slow to reach the city as insufficient funds had been provided for their travel – they were halted at Brentford for two months being unable to pay their lodging fees.

[2]: 285  The remaining eight companies had been intended to relieve Lieutenant-General Mordaunt's Regiment for service overseas, however they were never formed owing to the Peace of Utrecht bringing the war to a close.

[2]: 287 The invalid companies at Plymouth appear to have been successful in deterring a planned landing by the Duke of Ormonde, who had hoped to raise forces sympathetic to the Stuarts in the West Country in September.

[1]: 129 [1]: 171  A further detachment of 500 invalids was made available for service at sea in 1740, however Commodore George Anson was shocked at the disability and age of the men supplied.