Members of the public react to the new coins. Dani Sinha reports
The world got the first glimpse at the new coin this week, as the Royal Mint revealed the featured image of the King created by British sculptor Martin Jennings.The Royal Mint will sell the coin to collectors first, from early next week, before it is made available for general use before the end of the year.
One striking difference between the new King Charles 50p and coins featuring the Queen's likeness is that the two sovereigns' images are facing in different directions.
The choice is quite deliberate - and the Royal Mint has shared how subtle differences tell a story of long-held traditions, and the rare occasions those protocols have been broken.
Coins featuring both monarchs will continue to circulate in years to come, allowing them to be compared side-by-side, revealing several subtle differences.
Why isn't King Charles wearing a crown on the new coins?
Coins featuring the Queen's image always portrayed her wearing a crown. Previous Kings were traditionally never featured wearing a crown on coins.
But Her Majesty was featured in variations of the royal headwear during the five times her image was changed on coins during her 70-year reign.
During the sixties, the Queen as a young woman was featured wearing a laurel wreath.
When the second portrait of the Queen was introduced in 1971 as all coins were replaced due to decimalisation (when the United Kingdom converted to one basic currency unit, with the pound measured against pence sub-units calculated to a power of ten).After decimalisation, the wreath was replaced by a portrait of the monarch wearing a tiara.
A third portrait of the Queen designed in 1985 shows the Queen wearing the royal diadem, which she wore to and from the opening of Parliament.
The fourth and fifth portraits also showed her wearing a crown. The final design, by Royal Mint engraver Jody Clark in 2015 pictured the Queen in the Royal Diamond Diadem Crown, which she wore for her Coronation in 1953.
Why do the King and Queen face in different directions on coins?
The Queen was always pictured faced right on her coins in a tradition which has been place for more than 300 years, according to the Royal Mint.
Each King or Queen faces in the opposite direction to the one who came before them - which is why King Charles is pictured facing left.
The Queen’s father George VI had faced left on his coins, so tradition demanded her portrait face right.
Has that tradition ever been broken?Coin collectors covet a 1937 coin that captures a rare break in that tradition, and captures an important period in royal history that led the Queen to the throne.Princess Elizabeth was not originally destined to be Queen. Her uncle, Edward, was in line to ascend to the throne.
But his romantic involvement with American socialite Wallis Simpson led to a constitutional crisis - as sovereigns were not permitted to marry divorcees.
He chose to abdicate after a reign of just 326 days, so that he would be able to fulfil his desire to marry her. His younger brother instead took the throne, becoming King George VI.
When the King died in 1952, Princess Elizabeth would immediately acceded to the throne to become Queen - and the rest is history.
But coins featuring the 'King who never was' were created.
Official coins featuring Edward VIII were never issued in the UK. However preparations did start on their design in 1937 - and some of these renditions can still be seen in the Royal Mint's museum today.
On those coins, Edward faces left- in a break from tradition.
Why? The royal apparently felt that captured his better side.
The Royal Mint had been torn over two proposed portraits of Edward, and took the step of asking his opinion.
The royal felt one of the options made him appear too stern - and opted for the portrait he felt was more flattering.
Because George V faced left, Edward should have been featured facing right on his coins.
But according to the Royal Mint's history of the episode, Edward declined to follow the custom of each new monarch’s effigy facing in the opposite direction to their predecessor.
Edward insisted his portrait show his favoured left side as he felt showing his hair parting would 'break up the appearance of an otherwise solid fringe of hair,' the Royal Mint says.
Because the coins were never issued into circulation after Edward abdicated, the coins are not 'official' - but are coveted by collectors for their rarity and intriguing back-story.
Why do coins feature monarchs?
The tradition dates back to a time before photography and widespread access to portraiture in art galleries and museums could show the public what the reigning monarch looked like.
Coins also helped spread a monarch's fame in lands far and wide, as their image was passed around abroad by traders and plunderers swapping coins.
Athelstan, who reigned from 924 to 927, was the first English king to be shown on his coins wearing a crown or circlet.
The Royal Family's history documenting the reasons for coins bearing a monarch's effigy also points out that hundreds of years ago, a sovereign's image on a coin was the only likeness many people were likely to see in their lifetimes.
When can you get a new coin featuring King Charles?
The Royal Mint will be releasing a special collection of memorial coins to mark the Queen's death and the King's new reign.
There will be three memorial coins, each featuring three reverse designs - capturing both the Queen and the new official coinage portrait of King Charles III.
The UK 50p coin will also enter general circulation before the end of the year.
Coins featuring the King and the Queen will co-circulate in order to reduce environmental impact.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know