The Queen's death means that money, coins and stamps currently in circulation will be replaced with new ones to mark the new reign of King Charles III.
All 29 billion coins in circulation in the UK have the Queen's head on them.
The Royal Mint won't say how or when it will start issuing coins with King Charles III's head on them, but it's likely that the Queen's coins will remain in circulation for many years, and that the process to replace them will be a gradual one.
Coins featuring the new King will show him facing to the left.
It is a tradition from the 17th century to alternate the way successive monarchs are facing. Elizabeth II’s effigy faces to the right.
Read more: Queen's death mourned by the City
Banks and post offices will issue the newly designed coins and notes and collect the older versions.
A new portrait of King Charles III will be commissioned, from which millions of pounds worth of new currency will be printed by the Royal Mint and distributed across the UK.
The Royal Mint advisory committee needs to send recommendations for new coins to the chancellor and obtain royal approval.
Designs are then chosen and the final choices approved by the chancellor and then the King.
The Queen’s coins did not appear until 1953 — the year after her accession.
It’s not just British money that is affected by the change as the Queen’s image features on the currency of 35 countries worldwide — more than any other monarch.
These include Canada, Jamaica, New Zealand, Fiji and Cyprus, where she appears on some notes and coins due to her position as head of the Commonwealth. Some countries may even choose to keep currency featuring the Queen to honour her legacy.
All notes and coins will remain legal tender.
The new King will at some stage feature on British stamps, and others around the Commonwealth.
Since 1967, all stamps issued by the Royal Mail (RMG.L) have featured an embossed silhouette of the side profile of Queen Elizabeth II.
For her first stamps as monarch, the Queen was photographed by Dorothy Wilding three weeks after acceding to the throne and again around two months later, finally approving the image in May 1952.
The portrait from 1952 was replaced in 1967 by the famous sculptured head by Arnold Machin, accompanied by the tiny cameo silhouette of the Queen.
It's thought to be the most reproduced work of art in history, with more than 200 billion examples produced so far.
The new King has featured on stamps before, but Royal Mail won't yet say what the new designs with him will look like.
New stamps are shown to the Stamp Advisory Committee before a proof of the new design is printed, showing what the finished stamp will look like at actual size.
When the final proof has been approved by Royal Mail and the Stamp Advisory Committee, it is shown to the monarch for approval before printing.
As well as putting the monarch on stamps, the Royal Mail puts royal cyphers on many postboxes.
More than 60% of the UK's 115,000 postboxes carry the EIIR mark of Queen Elizabeth II — E for Elizabeth and R for Regina, which means queen.
At the start of the Queen’s reign in 1952, there were objections in Scotland to her being styled Elizabeth II because the Tudor queen Elizabeth I was never a queen of Scotland.
A Post Office pillar box in Edinburgh bearing the EIIR cypher was defaced and later blown up.
Its replacement was left blank.
British passports are issued in the name of the Queen with the wording: "Her Britannic Majesty's Secretary of State requests and requires in the name of Her Majesty all those whom it may concern to allow the bearer to pass freely without let or hindrance and to afford the bearer such assistance and protection as may be necessary."
As with currency and stamps, rather than a mass recall which would be both a huge operation and expensive, passports with this wording will be phased out as they expire.
New wording, reflecting the new king, will then take their place. Much in the same way we've seen the old burgundy passports replaced with blue ones after Brexit.
The reigning monarch doesn't need a British passport when travelling overseas, given that the document is issued in their name, and so King Charles III won't need one.