More than £63 million in Premium Bond prizes have yet to be claimed by winners across the UK.
There are still five prizes worth £100,000 left where no winner has come forward, as well as lots of smaller amounts waiting to be claimed.
This includes 92,000 unclaimed prizes in Scotland, and 559,000 unclaimed prizes in London and south east England.
An unclaimed prize is classified as one that has not been claimed within 18 months of it being won. There is no time limit to making a claim.
NS&I, which runs Premium Bonds, contacts winners when they have a prize to claim, however sometimes this does not work if contact details are not up-to-date or letters get lost in the post.
And sometimes people may not know that they could potentially be due a letter, having forgotten about bonds they bought a long time ago or were given as a gift.
How to check if you have Premium Bonds
If you think there is a chance that you could have Premium Bonds, but you are not sure, there is a tracking service on the NS&I website.
To check if you have any bonds you need to fill out a form with your personal details and send it off. If you do have Premium Bonds, then you will be contacted.
How to check if you have won a prize
If you know you have bonds and want to find out if you are owed a prize, you can also do this on the NS&I website.
To do so you need your unique holder’s number, which can be found on your bond record or by logging into your account on the NS&I website.
It is a nine or 10 digit number, or an eight digit number with a letter at the end.
You then need to enter this number into the prize checker and it will tell you whether you are due to claim a prize or not.
You can also use your NS&I number to check if you have won a prize, but this can only be done in the app and not on the website.
If you have an NS&I number, you'll find it on most communications you've had with them.If you only know your bond numbers, or have lost your documents, then the only way to find out if you have won a prize is to write to NS&I and request a bond record.
This will show all the bonds you hold as well as your holder's number and your NS&I number.