The special coins were set to be imprinted with the Brexit date of 31 October, but it now looks like Britain will not have left the EU by then.
Three million of the special 50p coins were due to be released into circulation at the end of this month on the planned leave date of 31 October.
A further seven million of the coins were then to follow within the year, each emblazoned with the words ‘Peace, prosperity and friendships with all nations’, along with the exit date.
The 50p was expected to join a line of several EU-inspired coins in the UK, including one marking when the country joined the European Economic Community in 1973, and when the UK held the presidency of the EU Council in 1998.
However, with Boris Johnson's Brexit timetable now in doubt, the UK is awaiting a verdict from the EU on the possibility of a third extension, making the planned exit date of 31 October highly unlikely.
Will the coins still be released?
With a Brexit delay likely, the date on the coin will presumably be altered again, having already been changed once before from the original leave date of 29 March 2019.
While three million of the coins were due to be in circulation by the end of this month, only around 1,000 are thought to have been created as part of a trial run, according the The Telegraph.
Responding to questions about the production of the coins on Twitter yesterday (23 Oct), the Royal Mint said, "We can confirm that Royal Proclamation has been passed for a fifty pence coin commemorating the UK's departure from the European Union.
"This means the coin has become legal tender, and we will begin production in time for the UK's departure from the EU."
How much could the coins be worth?
If the UK's departure from the EU is delayed, coins featuring the October date would effectively have an error, thereby increasing their value to collectors.
Coins with minting errors are of high interest to collectors, due to their rarity.
eBay sellers are already listing pre-order Brexit 50p coins for hundreds of pounds and, with limited availability, they could yet further increase in value.