The first £1 coins bearing the portrait of King Charles III are entering circulation this week.

Almost three million coins have been issued to post offices and banks across the country.

The coins mark the King’s new reign and celebrate his love of the natural world, with the reverse side featuring a pair of bees.

Even as the King becomes a familiar sight on coins, those featuring Queen Elizabeth II will remain in circulation. New sets of coins are struck in response to demand.

“It is an honour to reveal that King Charles III’s £1 coin is now in circulation,” said Rebecca Morgan, director at the Royal Mint.

“We know there’ll be a buzz of excitement amongst collectors and the public to get this special piece of history in their change.”

The bees are one of eight new designs that will appear on the nation’s coins, from the 1p to the £2.

The new designs of the coins were revealed back in October.

The tails side of every coin will feature the country’s flora and fauna. Animals ranging from the red squirrel to the capercaillie grouse are also depicted, as part of an effort to show the importance, and precariousness, of the natural world.

Ms Morgan said she hoped the designs across all denominations would spark “important conversations about the conservation of these important species”.

Each coin has been created with the support of the Royal Horticultural Society and the Royal Society for the Protection of Birds.

The size and shape of the coins remain unchanged, which is key because of the still widespread use of coins in vending machines, supermarket self-checkouts and parking meters.

But the numbers on the coins have been enlarged, to help children identify figures and learn to count.

The Royal Mint, based in Llantrisant, Rhondda Cynon Taf in Wales, has made the circulating coinage of each of Britain’s monarchs since Alfred the Great, Ms Morgan said.

Although there have been commemorative coins circulating featuring King Charles, these new designs – officially known as definitives – markthe King’s transition on to coinage that will be used daily.

Definitive coins feature the standard designs seen on the majority of official currency. These designs stay the same for years or even decades.

The previous set featured a shield formation and was introduced under Queen Elizabeth II in 2008, and will still dominate the 29 billion coins in circulation in the UK for some time yet.