After initial shore training, officers embarked in larger ships of the Royal Navy's fleet (usually battleships or battle cruisers) for one year, to familiarise themselves with gunnery and naval practice.

Although under the operational authority of the Admiral Commanding, Reserves, the RNR was administered jointly by the Admiralty and the Registrar General of Shipping and Seamen at the Board of Trade throughout its separate existence.

Officers and men of the RNR soon gained the respect of their naval counterparts with their professional skills in navigation and seamanship, and served with distinction in a number of conflicts including the Boer War and the Boxer Rebellion.

In their professional careers, many RNR officers went on to command the largest passenger liners of the day and some also held senior positions in the shipping industry and the government.

At the turn of the 20th century, there were concerns at the Admiralty and in parliament that the RNR was insufficient to bolster the manning of the greatly-expanded fleet in the event of large-scale war.

The pool of potential RNR officers had shrunk since 1859 and experience in the Boer War showed that it would not be possible to call up a sufficient number of reservists without negatively impacting the work of the merchant and fishing fleets.

Officers of the permanent RNR on general service quickly took up seagoing appointments in the fleet, many in command, in destroyers, submarines, auxiliary cruisers and Q-ships.

Fishermen of the RNR section served with distinction on board trawlers fitted out as minesweepers for mine clearance operations at home and abroad throughout the war, where they suffered heavy casualties and losses.

One such casualty was armed naval drifter HMT Frons Olivae, which hit a mine off Ramsgate on 12 October 1915 in an explosion that killed at least five other seamen.

One casualty, a Newfoundlander serving with the Royal Naval Reserve, was subsequently buried in the Hamilton Road Cemetery, Deal, Kent.

On commencement of hostilities in the Second World War, the RN once again called upon the experience and professionalism of the RNR to help it to shoulder the initial burden until sufficient manpower could be trained for the RNVR and 'hostilities only' ratings.

This was the Royal Naval Volunteer (Supplementary) Reserve, open to civilians with existing and proven experience at sea as ratings or officers.

[6] If still considered a CW candidate at the end of this period, they would become a Cadet Rating and proceed for officer training at HMS King Alfred.

Those who did not meet and maintain the required standards while as CW Candidates or while training at King Alfred would continue to serve as RN ratings.

[9] As intended, the thousands of RNVR officers employed during the Second World War on temporary commissions were quickly demobilised when the conflict ended.

Both reserves would now use the same style as the regular RN - officers would wear the straight stripes of lace but with an 'R' in the executive curl while ratings would be distinguished by 'RNR' and 'RNVR' cap tallies or shoulder flashes as required.

By 1957, it was considered by the UK government that the training required to operate modern equipment was beyond that expected of reservists and the Air Branch squadrons were disbanded.

(The US government took a different view, and the US Navy and Marine reserve squadrons today still operate front-line types alongside the regular units.)

The new unified reserve took the name and legal identity of the original RNR but primarily retained the character and structure of the RNVR, being composed mostly of trained civilians not from sea-going professions.

The service continues to adapt to conflicts; the AW Branch was formed following the Falklands War in 1982, when over 100 reservists volunteered for special temporary duties during, primarily serving in communications, intelligence, staff headquarters and medical roles.

The Strategic Defence Review in 1998 continued this by disbanding the 10th Minesweeping Squadron, meaning that the RNR no longer had its own ships and sea-going capability.

The restructured RNR was designed to "provide an expanded pool of personnel to provide additional reinforcements for the Fleet", mainly in the roles of logistics and communications - specialist support roles the need for which would expand significantly in the event of a major deployment or extended conflict but which it was not seen as viable to maintain within the regular RN's peacetime strength.

The centenary of the formation of the RNVR was commemorated by the RNR in London in 2003 with a parade on Horse Guards, at which Prince Charles took the salute.

The Blue Ensign of the United Kingdom has been worn since 1865 by British-registered merchant vessels commanded by active or retired officers of the RNR, when authorised by Admiralty warrant.