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Our Electronic Random Number Indicator Equipment, or ERNIE, was invented by one of the original Bletchley Park code breakers in 1956. Since then, he’s generated the numbers for over 327 million tax-free prizes worth approximately £16 billion.

The basic function of ERNIE hasn’t changed over the years. ERNIE generates numbers completely at random.

ERNIE 4 generates Bond numbers completely at random, no matter how long. So every Bond number, whether it has 8, 9, 10 or 11 digits has a separate and equal chance of winning a prize.

When ERNIE has randomly generated a list of numbers they're matched in order against eligible Bond numbers to determine the lucky winners.

Since 1957, there have been four generations of ERNIE. With continuous advances in technology, each has become faster and smaller. If ERNIE 1 were still in use today, it would take over 100 days to complete a draw. Our current ERNIE 4 only takes around 5 hours!

On Budget day, 17 April 1956, Harold Macmillan announced the launch of Premium Bonds. His intention was to reduce inflation and offer an alternative way to save.

Alderman Sir Cuthbert Ackroyd, the Lord Mayor of London, bought the first Premium Bond on 1 November 1956. By the end of that first day, £5 million worth had been sold. With £82 million invested, it was time for the first draw on Saturday 1 June 1957. There were 23,000 prizes in that first draw with a top prize of £1,000.

Our Agents Million deliver good news in person to the two jackpot winners. One Agent Million has told over 100 new millionaires about their good fortune.

Since 2010 we've given you more ways to manage and check your Premium Bonds. Anyone can see if they have won a prize by using our online prize checker or app. And of course you can buy more Bonds whenever you like, 24 hours a day.

  • Prize checker
  • Prize checker app
  • Premium


Got a question about yourExisting Bondsor need toupdate your details?

ERNIE is so famous that he receives Christmas and Valentine cards every year. He’s even gone on display at The Science Museum. Like many celebrity figures, over the years myths have grown up around ERNIE and Premium Bonds. Here are a few of them debunked.

  • Each month, the Government Actuary's Department (GAD) does an independent check to ensure ERNIE's output is random. GAD then issues a certificate to confirm that it has no reason to believe the draw isn't random. We can only publish numbers and pay out prizes when that certificate has been issued.

  • Jackpot winners have a varied amount invested – one winner of the £1 million jackpot only had £17 in Premium Bonds! However, the more Bonds you hold, the better your chances of winning.

  • Each £1 Bond has an equal chance of winning, regardless of when or where it was bought. Over 89% of eligible Bonds have been bought since the year 2000. So even though Premium Bonds have been on sale for over 50 years, this is why newer Bonds seem to win more frequently. When ERNIE randomly generates winners, he doesn’t store any numbers, so there’s no way any Bonds can be left out.

  • Winning numbers are generated randomly and then matched against eligible Bond numbers afterwards – numbers aren't entered into or stored in ERNIE so there's no way that any Bonds can be left out of the draw.

  • If it seems that more prizes are won by holders in the South East, that's because there are more Bonds held there compared with the rest of the UK.

  • Not at all. The prize fund for each draw is a month's interest on all eligible Bonds in the draw, so the more Bonds we sell, the bigger the prize fund.

Category: Savings

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