More than £100m of premium bond prizes remain unclaimed amid criticism that the government-owned bank which operates the savings scheme is not doing enough to find the winners.
There is a total of 2.5m unclaimed prizes - with 11 £100,000 prizes, 19 £50,000 prizes, 38 £25,000 prizes and 75 prizes of £10,000.
Premium Bonds prize winners should receive notifications of their winnings via text message, email or post if they have registered their details. Some customers, however, relocate and forget to update their details.
Other bond holdings are not registered. For example, people may be unaware they were gifted bonds as children, or they were never given the paper certificate carrying the account numbers.
Since the first draw in June 1957, its Electronic Random Number Indicator Equipment - known as ERNIE - has drawn a total of 772 million prizes worth a combined £37billion.
NS&I retail director Andrew Westhead said the bank recognised bonds purchased before digitisation were "much harder to trace".
Mr Westhead said: "The £103m of prizes currently unclaimed represents just 0.28% of the total £37bn awarded by ERNIE over nearly seven decades."
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