Over £40 million in premium bond prizes remains unclaimed, according to National Savings & Investments (NS&I).
Three quarters of a million premium bond holders have failed to claim their cash prizes, including one prize of £100,000, another worth £50,000 and four prizes worth £25,000.
The unclaimed £100,000 belongs to a woman from London who won it in February 2007 with just a £25 holding. Meanwhile, a woman from Kent is unaware she's sitting on £50,000, won with a £128 holding in November 2007.
NS&I is launching a nationwide search to track down the unaware winners – some of which have left their prizes unclaimed for over 50 years.
The oldest winner yet to claim is a man from South Yorkshire who won £25 in 1957. A number of 1960s winners are also yet to come forward.
Winners can choose to either receive their prizes by cheque or be paid directly into their bank accounts.
Gill Stephens, spokesperson for NS&I, says: "What often happens is a lot of holders have premium bonds bought for them when they are younger and they forget about them. They then move address and the winnings are posted to an old address, then returned to us."
Top 10 unclaimed prizes in the UK
|Winning bond number||Prize value||Gender||Last known location||Present premium bond holding||Month and year of draw|
How to claim
To find out if you are sitting on a missing fortune, use NS&I's premium bond checker nsandi.com/savings-premium-bonds. All you have to do is enter your holder number.
If you lost, or you don't know, your holder number you can write to NS&I at Premiums Bonds, National Savings and Investments, Blackpool, FY3 9YP. You can also call its hotline on 0500 007 007.
Ranging in value between £25 and £1 million, approximately 1.7 million prizes are handed out each month.
Holders can invest as little as £50 a month and up to £30,000.
Premium bond holders have a one in 427 million chance of winning the £1 million top premium bond prize in the November draw, based on a £100 investment, according to NS&I.
The odds of winning any prize are 24,000 to one per £1 unit.