Britain will gradually see coins, banknotes and stamps bearing the image of King Charles, while the new monarch's cypher will also appear on government buildings and red mail pillar boxes.

King Charles' new monogram has been revealed ahead of the official period of royal mourning for the death of his mother, Queen Elizabeth II, coming to an end.

The new cypher will appear on government buildings, state documents and on some post boxes in the coming months and years.

The cypher features the King's initial "C" intertwined with the letter "R" for Rex – which is Latin for King – with "III" denoting Charles III, with the crown above the letters.

"The first coins bearing the effigy of His Majesty King Charles III will enter circulation in line with demand from banks and post offices," Royal Mint chief Anne Jessopp said.

"This means the coinage of King Charles III and Queen Elizabeth II will co-circulate in the UK for many years to come."

The Royal Mail said the current picture of the late Queen used on "every day" stamps would be updated to feature an image of Charles, with the new stamps to enter circulation once current stocks are exhausted.

All existing currency and stamps bearing the Queen's image will remain valid.