By Julian Knight
Personal finance reporter, BBC News
Since 1994 when the £1m premium bond prize was introduced, 168 people had their lives changed forever.
With premium bonds 50 years old, BBC News talked to a lucky winner and to National Savings and Investment's "Agent Million" - the man who gets to break the good news.
MILLION POUND WINNER HANNAH PETERSON (not real name)
Hannah Peterson's life has been one of contrasts.
For the first 70-odd years of Hannah's life, things were often a financial struggle.
"At one time I worked at three jobs and looked after an elderly relative," she recalls.
Hannah was not able to put much aside and was living off a pension of £110 a week when Agent Million came knocking.
"It was Sunday afternoon and the agent came to the door.
"I let him in and at first I was worried that there was something wrong with my bonds - I thought perhaps I was going to have them taken away."
Hannah's concern was rooted in the fact that the £3,000 she had in premium bonds was a large chunk of her life savings.
"I have had premium bonds off and on for 50 years and only won once - £25 in the 1960s - I did not even know there was a million-pound prize.
"When he told me I had won I was completely shocked, I nearly fainted."
"I remember that night pacing around not knowing what to do. I almost made myself ill thinking about the money. I could not get my head around the million pounds."
Over the next few months, Hannah's new reality sunk in.
"National Savings arranged for me to get independent financial advice, which helped enormously.
"I moved out of my semi-detached house and into a detached house in the village I was born. I do not have much family. I was divorced nearly 50 years ago."
Hannah also travelled extensively for the first time.
"I went on cruises," she says, "but the highlight was a river boat trip along the Mississippi."
But as far as Hannah is concerned, the money is not about just a nice home or exotic trips.
"I now have security. I no longer worry when the bills fall through the letter box.
"That is a wonderful feeling."
Agent Million has been working for National Savings for 27 years - but only in the past two years has he been one of the two NS&I employees who share the job of visiting prize winners.
One of the two people with the job of being "Agent Million"
"When I turn up at someone's door, I am often greeted, initially, with suspicion.
"I remember one Halloween, with the trick-or-treaters out and about, the prize winners just would not believe I was who I said."
Agent Million carries identification with him, as well as a letter from the head of National Savings.
"First I have to find the winner. I do this through the electoral roll and from looking at the address where previous, smaller, prizes have gone too.
"I ask for proof of identity, just to ensure I am speaking to the right person, and then once I get it I ask if they would like to go somewhere private for me to tell them something important regarding their National Savings investment."
Once the winner is sitting down, Agent Million breaks the good news.
"I hand over the letter from the head of National Savings and as they open it I say: 'Congratulations - you have just become the million pound prize-winner'.
"As you can imagine, reactions range from complete disbelief, shock, to instant delight.
"I had one lady who ran around and around her garden, shouting and waving her arms around. We had to make her a cup of sweet tea to help her calm down.
"Who wins is purely down to chance, so therefore there are some winners who really need the money and others who don't.
"The people I visit come from all backgrounds. For some you can clearly see that it is a life-changing event allowing them to retire and help out their loved ones.
"Other people, though, are already wealthy - for them it is an addition to their portfolio."
Agent Million loves his job.
"It is great to bring such joy and one of the nicest parts of the job is that some winners stay in touch. I get Christmas cards and postcards from all the exotic locations they are travelling too.
"It is really wonderful."
One winner in particular sticks in Agent Million's mind.
"There is one elderly lady, in her 80s, who had never travelled and was living on a state pension.
"I got one card from her after she had just gone on a helicopter trip across the Grand Canyon."