A new portrait of the Queen that will appear on coins has been unveiled - but it may be some time before the updated money starts showing up in people's wallets.
The effigy is only the fifth definitive coin portrait to have been created during the Queen's reign and it has been designed by Jody Clark.
Chief engraver at the Royal Mint Gordon Summers described the task as "probably one of the most difficult things for any artist or sculptor to do".
Mr Clark is the first Royal Mint engraver to be chosen to create a definitive royal coinage portrait in more than 100 years.
Aged 33 when his design was selected from a number of anonymous submissions to a design competition, he is the youngest of the five designers to have created the portraits of the Queen that have appeared on UK circulating coins during her 63-year reign.
He said: "I really liked the four previous coin portraits - each one is strong in its own way.
"I hope that I've done Her Majesty justice and captured her as I intended, in a fitting representation. The news that my design had been chosen was quite overwhelming, and I still can't quite believe that my royal portrait will be featured on millions of coins, playing a small part in the Royal Mint's 1,000-year history."
The portrait shows a side profile of the Queen wearing a crown and drop earrings.
Mr Clark, who is o riginally from the Lake District and who celebrated his 34th birthday yesterday, said his family are "really proud", adding: "They've had to keep quiet about this.
"It's going to be hard to top this. It's going to take a while to sink in."
He said his top priority was to create an "accurate" representation of the Queen.
He added: "I'm really happy with how it's turned out. I can only hope everyone appreciates it."
Kevin Clancy, director of the Royal Mint Museum, said the judging panel's decision was "pretty unanimous" and added that this latest portrait is "astonishingly significant". He said it had "a good likeness and a dignified likeness".
Mr Clancy said there was not a "strict brief" sent to potential designers.
Mr Clark's portrayal of the Queen, wearing the Royal Diamond Diadem crown worn for her Coronation, was selected in a closed competition organised by the Royal Mint Advisory Committee (RMAC), a consultative panel to HM Treasury comprising experts from such fields as history, sculpture, architecture, art and design.
A number of specialist designers from across Britain were invited to submit their own interpretations of the Queen's portrait under anonymous cover, and each one was judged on its merits and suitability before the winning artwork was recommended to the Chancellor and, ultimately, the Queen for approval.
Adam Lawrence, chief executive of the Royal Mint, said: "This change of royal portrait will make 2015 a vintage year for UK coins, and it will be hugely exciting for us all to see the new design appear on the coins we use every day.
"Jody's achievement is something that we can celebrate as a proud moment for the Royal Mint.
"Capturing a portrait on the surface of a coin demands the utmost skill, and is one of the most challenging disciplines of the coin designer's art.
"The last Royal Mint engraver to be commissioned to undertake a royal portrait was George William de Saulles, who engraved the portrait of Edward VII which first appeared on the coinage in 1902."
Coins featuring the new effigy go into production today and the public are being urged to keep an eye on their coins later this year when it will start to appear.
New coins tend to be delivered to cash centres and banks in the first instance.
The unveiling took place at the National Portrait Gallery in central London.
The Royal Mint announced the date of the unveiling of the new portrait in January, to mark the 50th anniversary of the death of Nottingham-born sculptor Mary Gillick, who was the first artist to capture the Queen's portrait for the nation's coins.
Issued in 1953, the Gillick portrait depicted the Queen wearing a wreath of laurel, rather than the crown that we are used to seeing today. The portrait, which is still struck on Maundy Money, was considered to reflect the country's optimism as it greeted a new monarch in the post-Second World War era.
The most recent portrait of the Queen on coins has been appearing since 1998. It was created by Surrey-born artist Ian Rank-Broadley, whose aim was that the portrait should be recognisable and not "over-idealised''.
While artists' interpretations of the Queen's image have changed over time, one tradition which has remained constant is that the Queen has continued to be depicted facing right. This is in accordance with a tradition that can be traced back to the 17th century, whereby successive monarchs face in alternate directions on coins.
According to the Royal Mint Museum, some people believe that this tradition could originate from the desire of Charles II to turn his back on Oliver Cromwell, although the museum suggests that this may be too convenient an explanation and it might be better to concede that if any reason has existed for this, it has long since been forgotten.
The museum said that even during the long reign of Queen Victoria there were no more than five portraits of her on coins, one of which enjoyed such royal favour that it was used for some 50 years.
There were estimated to be around 28.9 billion UK coins in circulation at March 31 last year, with a total face value of more than £4 billion. They were all manufactured by the Royal Mint, which has a history of more than 1,000 years of producing British coinage.
The Royal Mint said that existing coins which are in current use will remain in general circulation until they are naturally recycled due to wear and tear, usually when they are around 20 to 25 years old, and their use will not be affected by the new portrait.
Mr Clark, originally from Bowness-on-Windermere, studied illustration at the University of Central Lancashire before gaining experience in computer-aided design in the packaging industry, among other freelance illustration and design projects.
Since embarking on his career at the Royal Mint, he has worked on projects such as the medals struck to celebrate the 2014 Ryder Cup and a Nato summit.