This is the exact detail to spot on a rare 50p to see if it's worth as much as £40,000 at auction.

The Brexit 50p was released in 2020 to mark Britain's dramatic exit from the EU.

A COIN expert has revealed the exact detail to spot on a rare 50p to see if it's worth as much as £40,000 at auction.

The Brexit 50p was released in 2020 to mark Britain's dramatic exit from the EU.

It bears the official Brexit date - January 31 - along with the message: "Peace prosperity and friendship with all nations."

But what many people don’t know is that millions of the coins were originally minted with a different date – October 31, 2019 - when Brexit was originally supposed to take place.

When it was delayed, these coins were supposed to be melted down – but some made it into circulation.

A total of 10,001,000 Brexit 50p coins with the correct date of 31st January 2020 were put into circulation, making them relatively common.

But those with the earlier date are extremely rare and highly sought after by collectors.

This is the Brexit 50p, released in 50p, to mark the UK leaving the EU

But did you know the Royal Mint accidentally printed a batch of these coins with the original October 31 2019 date?

Some coins were originally struck in 2019 for the first Brexit deadline but when Brexit was delayed, those coins were supposed to be scrapped

A few slipped through with the original 2019 date and because they weren’t officially released they’re insanely rare

We’re talking only a few known to exist and they sell for a small fortune

Coins like this one sold for an incredible £40 000 at auction

Don’t spend it you might be holding a coin worth more than a car

The coins are really only worth what someone else is willing to pay for them and they vary in price depending on the condition and grading of the coin

This coin sold for an incredible £40,000 at auction to one lucky seller.

The coins are really only worth what someone else is willing to pay for them and they vary in price depending on the condition and grading of the coin.

A third version of the coin was also minted to mark the first proposed Brexit date of March 29 2019.

The March coins were also recycled after the updated deadline - with any surviving coins potentially worth in the tens of thousands.

And this isn't the only 50p that can bring in a small fortune.

Last month, another 50p coin sold for almost 500 times its face value, fetching a whopping £245.

The coin featured lines across a swimmers' face which made it incredibly rare and sought after.

The "Lines Over Face" Aquatics 50p was first struck in 2011 and then tweaked to make the face more visible.

Designed by Jonathan Ollife, the coin has been described as "extra special" by the Royal Mint, which creates the UK’s currency.

How to check if your small change is useful

If you think that you might have a rare coin then it’s worth checking with an expert to see if yours could sell for a hefty price tag.

The most valuable coins are usually those with a low mintage or an error.

These are often deemed the most valuable by collectors.

You can check how much the coin is selling for on eBay by searching the full name of the coin, selecting the "sold" listing and then toggling the search to "highest value".

It will give you an idea of the amount of money that the coin is going for.

But it's not always the case that a coin has sold for the amount is was listed for.

Coins are really only worth what someone else is willing to pay for them.

Sometimes, collectors are willing to pay more for a coin if they need it to complete a set.