There’s the Royal Navy, the Royal Marines, the Royal Air Force …
… but the British Army.
Why is that? The army not good enough to be royal?
It’s the British Army but many Regts. are named thus:
Royal Engineers
Royal Signals
Royal Artillery
etc, etc
I’m guessing that it’s because most of the army forces originated as feudal units. The king was joined by dukes and earls and barons who all led their own troops. It would have been impolitical (and untrue) to call this force the Royal Army.
The navy however was raised and controlled directly by the king, as were other units like the ones chowder mentioned.
Exactly.
The King ran the entire Navy from the get-go, but the Army grew out of local levies and such that were not his. So Lord Pantywaist’s Light Horse was Lord Pantywaist’s an nobody else’s. The HMS Raging Queen was paid for by the King, so it (and the Navy as a whole) were “Royal.”
This question seems to come and goes on the boards, IIRC it’s because the King of England got his power from the various lords who served him, so the army fielded was made up of many different smaller armies.
The navy was there to defend the entire country and could not be turned against the populace, so it was funded by the government and controlled by them.
Minor nitpick - the Engineers and Signals are actually “Arms” rather than regiments but the principle is right.
Little Nemo’s guess about the different origins of the different units is partly right but but I don’t think any of them started as feudal retainers of the great aristocrats. The various infantry regiments can trace their origins back to various points in time but I don’t think any of them go back beyond the 17th century.
As I remenber it the oldest regiment is the Royal Scots (The First of Foot) which just predates the Civil War. Generally regiments were raised by an individual at the request of the Crown (or Parliament during the Civil War) and were known by the name of the Colonel.
There is one private,feudal army left in the UK - it belongs to the Duke of Atholl and is not part of the British Army!
I thought that King Henry VIII outlawed private armies, as they were a threat to his authority.
Anyway, what is the status of outfits like the “ANCIENT ARTILLERY COMPANY”? We have a similar group, here in Boston, MA-the “Ancient and Honorable Artillery Company”-its a collection of rich guys who dress up in uniforms.
Their slogan is: “Invisible in war, overwhelming in peace” 
Most Commonwealth Realms maintain the tradition (eg Royal Australian Navy, Australian Army, Royal Australian Airforce, etc). Canada used to have a Royal Canadian Navy and Royal Canadian Airforce before they unified their military in the '60s. The Canadian navy still prefixes it’s ships with HMCS (Her Majesty’s Canadian Ship).
The Honourable Artillery Company, which has been around since the 16th century, is actually part of the Territorial Army - the British Army’s volunteer reserve - and individual members have been mobilised to serve in Iraq and Afganistan in the last couple of years.
I don’t know if it is still true but the story I was told many years ago was that their artillery officers always did well on firing exercises as it they were mostly super smart city whiz kids who found the calculations child’s play!