They say cash is king – but a rare coin from the reign of Queen Elizabeth II could be worth a pretty penny if you are lucky enough to possess one.

According to one TikTok user with an interest in old and valuable coins, a 1954 penny has achieved an estimated value of £90,000 – and could fetch in excess of £100,000 when it goes under the hammer this month.

In a video posted to his nearly 210,000 followers, user @CoinCollectingWizard gives an overview of the valuable coin, which is set to be sold under auction by Sovereign Rarities on 19 November.

Holding the coin in his hands, the expert first shows the reverse, which features a beaded border and the figure of Britannia – the female personification of Great Britain.

Britannia is seated facing right, wearing a crested Corinthian helmet and a flowing dress.

She rests her right hand on a shield bearing the combined heraldic crosses of the Union Flag, and a trident in her left, while in the background are sea waves and a lighthouse.

Britannia sits within the words ‘One Penny’ and the date, 1954, appears at the bottom.

Turning the coin over, the expert shows the young laureate bust of Queen Elizabeth II facing right.

A laurel wreath in the Queen’s hair is tied with a ribbon and two ends flowing behind.

Around the edges of the coin are the Latin words for ‘Elizabeth the Second, by the Grace of God, Queen, Defender of the Faith.’

User @CoinCollectingWizard says: ‘And this just happens to be a 1954 penny, the rarest penny the rarest penny ever known, even rarer than the 1933 penny.

‘As you may know the 1933 penny recently sold at auction for over £100,000.

‘And now that a 1954 has appeared at an online auction, we know have an estimate for this coin between £90,000 and £100,000.’

The video has so far garnered more than 660 likes.

According to vintage coin experts, Online Coin Club, the 1954 penny is thought to have the ‘highest rarity possible’, adding it is ‘one of the mysteries of British numismatics.’

Before it was minted, there were already a large number of pennies in circulation and an economic slowdown after the Second World War meant there was no demand for any more.

But when George VI died in 1952 at the age of 56, new coronation coins were designed to mark the ascension of Elizabeth II.

In 1953, more than 1.3 million pennies were minted for special commemorative sets, with an additional number put into circulation.

Online Coin Club explains that during this period the Royal Mint ‘experimented’ with the design.

At least one penny – though it could be many more – was minted bearing the year 1954, but these were intended for internal purposes only at the Royal Mint.

The trial pennies were meant to have been destroyed and were not for wider circulation.

Online Coin Club adds: ‘In response to a freedom of information request in 2011 the mint stated it was “unable to say for certain that only one survived from the trial run of several hundreds,”‘ prompting the tantalising assumption there could be others.

The British Museum and the Royal Mint Collection both have examples of the experimental coins, including some that were only struck on one side.