Eighty-one years ago this week the RMS Queen Elizabeth (above) was launched by her namesake, later the Queen Mother.

As well as being one of the most luxurious ocean liners ever, the Queen Elizabeth, along with her Cunard sister ship the Queen Mary, was also responsible for transatlantic mail transit.

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BT’s forerunner, the GPO, was central to UK communications, contracting ships to deliver mail across the ocean from the early Victorian era. Here’s a look at the rich history of Royal Mail Ships.

The first mail ships

The Royal Mail Ship (RMS) distinction was first awarded in 1841.

Originally, RMS vessels were run by the Admiralty as part of a contract with newly-formed Royal Mail Steam Packet Company (RMSPC). It provided 14 purpose-built vessels for the service.

The first RMS ships were named after British rivers (Thames, Trent, Severn, Avon, for example) and sailed to Barbados twice a month. From 1850 a South American route was added.

Diplomatic incident

In 1861, the RMS Trent almost provoked war between the US and the UK. In an incident known as The Trent Affair, during the American Civil War, the vessel was intercepted by the USS San Jacinto, sparking a diplomatic crisis: on board were two Confederate diplomats heading to Britain and France to seek recognition for the Confederate States.

The Union threatened war, while the affronted Brits (who had not chosen a side in the Civil War) demanded an apology and strengthened its military presence in Canada and the Atlantic. France had Britain’s back too, so President Abraham Lincoln eventually released the envoys to avoid conflict.

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The age of the ocean liner

Around the turn of the 20th century, passenger liners also began receiving RMS distinctions.

As well as ensuring lucrative contracts, the designation was considered a mark of quality for passenger ocean liners. Because the mail had to be on time, passengers could rely on it too. Stern penalties were issued for every minute the arrival was delayed.

As with many Royal Mail designated ships, twin ships the RMS Lusitania and the RMS Mauretania (launched in 1906) were designed with its mail subsidy in mind. The ships' stipulated service speed was 24 knots in moderate weather, and the two sparred for the title of fastest Atlantic crossing during their first years in service. 

Titanic clerks put the mail first

The RMS Titanic is arguably the most famous ship to bear the RMS title. She had a designated compartment for mail on G deck.

There were five Sea Post clerks on board, Englishmen Jago Smith and J. B. Williamson, and American employees of the US Post Office Department John S. March, William L. Gwinn and Oscar S. Woody, who was celebrating his 44th birthday when the ship struck an iceberg in April 1912. All five men perished.

According to an article in the Smithsonian National Postal Museum's EnRoute newsletter, the five men sacrificed any chance they had of survival by attempting to save the mail. 

"From available information, within minutes after the collision, the mail storage room, which was located well below the ship’s water line, began flooding, sending some of the mail sacks adrift," reads the report.

"Frantically, the clerks brought as many sacks as possible up to the sorting room in preparation for moving the mailbags onto the deck for possible recovery by a rescue ship. According to the Postmaster General’s 1912 Annual Report: 'The last reports concerning their actions show that they were engaged in this work . . . to the last moment'."

In all, 3,423 sacks of mail were lost. They contained over seven million items of mail (including 1.6 million registered letters and packages). An estimated $150,000 in postal money orders was also lost. It is thought some of the mail may have survived at the bottom of the North Atlantic.

Titanic

Although the wreck of the Titanic is protected by a United Nations convention and thus cannot be tampered with, the 105-year-old mail still on board could arguably be considered an exception due to postal service obligation.

The ship that came to the rescue of the Titanic's few survivors, the Carpathia, was also a Royal Mail Ship.

[Read more: Explore the UK's postal history at the Post Office Museum]

The sinking of the Lusitania

During the First World War, a German U-boat torpedoed the RMS Lusitania, killing 1,198 passengers and crew. The May 1915 sinking sparked a diplomatic crisis, because Lusitania was officially an unarmed, non-military boat. However, the Germans argued the cargo containing war munitions made it a legitimate military target. Because 128 American citizens went down with the ship, it became a factor in the United States joining the war in April 1917.

BT Archives - RMS ships

Many RMS ships were repurposed for military use during the war effort. The Mauretania served as a troop ship and also hospital ship for allied casualties. When the US eventually joined the war in 1917, she carried thousands of American troops over the Atlantic. She returned to civilian service in 1919.

RMS Queen Elizabeth

In 1932 the RMSPC was liquidated after falling into financial trouble. Its assets were taken over by Royal Mail Lines Ltd, which enabled operations to continue.

On September 27, 1938, the Cunard Line’s RMS Queen Elizabeth was christened. Her life as an iconic passenger liner was delayed until after World War II, but she was contracted as a mail ship between Southampton and New York for more than 20 years.

The RMS Queen Elizabeth served with distinction as the world’s largest passenger ship until its retirement in 1968. It was sold to a Chinese shipping tycoon who turned it into a university campus. However, it sunk in 1972 following an arson attack in Hong Kong harbour.

The RMS Queen Mary is permanently docked in Long Beach, California. It is now a stationary hotel with tours, on board attractions and dining experiences. An overnight stay during September cost from $109 (around £80).

[Read more: How the UK got connected]

Still going strong

Of the more than 200 vessels to have been designated Royal Mail Ships, only four remain in active service and only one of these - the RMS St Helena - delivers mail. 

The St Helena delivers the post - and absolutely everything else - from Cape Town to the remote British territory in the South Atlantic of the same name. The ship - which carried passengers and cargo between the UK and the island from 1989 until 2011 - had been due to leave service in 2010 when the island's £240m airport became operational, but concerns over wind shear have delayed the airport's opening indefinitely and the RMS St Helena remains in service. 

The Queen Mary 2, the transatlantic liner which launched in 2004, was given the RMS title by the Royal Mail as a nod to Cunard's heritage.

The Scillonian III actually bears the title RMV (Royal Mail Vessel) and has carried passengers and cargo between Cornwall and the Scilly Isles since 1977.

Finaly, the RMS Segwun is the oldest surviving ship to carry the RMS title. Originally launched in 1887, the steam-driven vessel carried mail and passengers along the Muskoka Lakes in Ontario, Canada, and was given the RMS handle in 1925. Taken out of service in 1958, the Segwun was restored in 1981 and now offers sightseeing excursions and dinner cruises on the lakes. 

[Read more: The Queen Elizabeth Class aircraft carriers – 14 amazing technical facts]

To find more about the history of communications in the UK and BT’s important role, visit BT Archives.