Thousands of National Savings & Investments customers could have prizes retroactively cancelled after decades-old Premium Bonds were discovered, breaking rules about maximum holdings.

NS&I has started to cancel prizes that were won with bonds that unknowingly pushed savers over the £50,000 maximum limit.

Four years ago a similar clampdown found that roughly 18,000 customers had more than one set of Premium Bonds in their name, and had exceeded the limit. 

Britain’s biggest savings institution has now restarted the process of combining old accounts, after placing this administrative work on hold during the pandemic. However, savers have criticised NS&I for rescinding prizes because of old bonds customers never knew they held.

In some cases, the newly-discovered bonds may have been bought for a saver when they were a child, or purchased under a different name or spelling. 

One reader, who did not want to be identified, said his wife had received a letter cancelling £50 in prizes after NS&I discovered £350 worth of bonds bought for her as a child had pushed her over the maximum limit.

He said: “She has no recollection of these bonds, which is not surprising, because they will have been bought for her by her parents or her aunt when she was still a child. 

“She is 73 and her parents and aunt died some while ago, so she has no means of checking the history.”