I've handed out more than $2.5 billion in lottery cash. Not everybody reacts the way you'd expect.

• Andy Carter's job is to advise people who win big in the lottery.
• Some hide it from their families, he said, and others don't believe him when he says they won.

This as-told-to essay is based on a conversation with Andy Carter, who advises lottery winners for Camelot, the operator of the UK's National Lottery. The following has been edited for length and clarity.

When someone wins big on the UK's National Lottery, they get passed to my team. We deal with people who win £50,000 ($63,000) and upwards.

I've been doing this 19 years — the last time we tried to add up how much I've given away, we came to about £2 billion ($2.5 billion).

We're the team that looks after them — we're the midwife-type character in all this.

There's two parts to this job. There's the paperwork. We are in a really highly regulated industry where everything needs to be spot on.

And then there's the second part, which is the welfare side. Most people haven't had, say, £5 million in their life. So how would you know what to do?

We have a follow-up meeting with a legal expert, a lawyer or solicitor and a financial expert, there's a whole load of support for as long as they want it. We are very much not about just throwing the money at someone and running off into the distance.

Once you are a winner [with us], you are always one. Some people keep in touch for us for years telling us what they've been up to.

In that first phone call, it differs from person to person.

If you've just found out you've won £5 million, you are probably going to be in shock. Your brain will be going a thousand miles an hour. You probably have lots of questions. Some people are literally gabbing away at me. Other people are very, very quiet.

I've had some people take the day off work because they're waiting for my phone call. And I've had others who said: "I'm at work, I'm actually going into a meeting, can you call me tomorrow?"

My theory is everyone has their own version of a "jumping up and down" moment, whether that's whooping for joy, or sitting quietly on a beach by themselves.

Some people don't even tell their families

There's lots of funny incidents when people don't tell their loved ones about the win.

A colleague of mine who went to see a winner who had a young baby, and the winner said: "I think my mum's coming over. Could you pretend to be the health visitor?"

So when there was knock on the door, my colleague had to hold the baby, as if to say she had a completely different job.

I've dealt with husbands who haven't told wives and wives who haven't told husbands. Some people don't tell the other half because they have some marital difficulty.

But there was one guy once, and I was at his dinner table completing all the paperwork, and he kept looking anxiously out the window, and asking me: "Are you going to be very long?"

I told him I'd be another half hour. He said: "My wife has gone to the supermarket and she's going to be back soon." It turned out he hadn't told her.

He said: "Don't think this is odd, but I love that woman. We've been together 30 years. I love the bones of her, but she doesn't know how much money I've got and I don't know how much money she's got. It's just the way we operate."

And there was something in his demeanor that made me think he's not lying to me, that it's just the way that they work.

It wouldn't go down very well in my house. But it was amazing.

Occasionally, they're very, very suspicious of me

There's a handful of people — they're a real minority — who really struggle to believe it's true.

There was someone the other day who said to me: "You are scamming me."

I sat there with this person, and he just didn't believe it.

It took me a while to persuade him, even though he'd played the lottery every week since it started in 1994.

And I said, "So every week for the last 29 years, you've been giving us money, and we've given you very little back, and you didn't think that was a scam.

"And now we are giving you some money back, and you do think it's a scam."

And he said: "Good point."

The biggest surprise is how careful most winners are

We found that after the 2008 financial crash, people became more financially conservative, and probably a bit more financially savvy.

The biggest misconception people have about a lottery winners is that everyone goes out and blows their money. It couldn't be further from the truth.

The British public are overwhelmingly very, very conservative with their lottery win. The amount of people who go out and buy a Lamborghini is pretty low, percentage wise.

You might think, "I want to go and buy a boat and float around an island." But actually, you realize firstly just I need to pay my mortgage off, or to look after my kids — the real practical stuff.