An hour before the kids get home from school on Friday, I check the kitchen drawer where I’ve left about 400 condoms for the boys. It’s virtually empty. Clearly it’s been a busy week on the sexual front in my small house. Nothing to do with me and I’ve been in all week, so I know there’s been no action within these four walls.

I make a cup of tea and mull it over. It’s been a hectic week.

Last Friday, the landline rang. As it usually means it’s someone over 40 calling, nobody else answers, so I do. But it was my son Ben’s best mate; sunny, chatty Danny. He sounded like he was a million miles away. He asked if Ben was in and when I said yes, he explained he needed to talk to him and was coming straight over. And he was gone.

I told Ben, who looked shifty. Nothing unusual in that.

I guessed the call had something to do with last Saturday’s sleepover at another friend’s house. Danny had siphoned off the top inch of spirits from his parents’ collection and mixed them into such a lethal cocktail that he was hospitalised and his dad was called.

When Danny arrived, he was ashen and barely looked at me as he headed upstairs. Five minutes later, I heard sobbing. Ben came down and waved me up urgently.

Danny sat on the bed, head down, face blotched, shoulders shaking. Ben told me what was wrong. Two and half months ago, Danny had sex for the first time. The 16-year-old girl told him she was on the pill. She wasn’t.

Now she was pregnant with twins and keeping them. Danny kept repeating that his life was over and this was why he’d got so drunk at the party. He couldn’t face telling his parents. Ben asked me if I would. You could hear a pin drop. They both looked at me, pleading.

It was not an easy job. I felt for them all. I also thought, breathlessly, that it could happen to my kids so easily. The UK has the highest rates of teenage pregnancy and abortion in Europe according the Family Planning Association. The average age for first time heterosexual sex is 16 for girls and boys.

As a youth worker, I spend a lot of time dealing with problems arising from drugs, drink (sometimes that’s the parents’ problem), social media, contraception, pregnancies and sexually transmitted infections (STIs). All in no particular order.

The Monday following Danny’s revelation, and with his parents’ shell-shocked faces in my head, I am in the waiting room of an STI clinic. I’m accompanying 17-year-old Ella. She thinks she may have chlamydia. It’s an easily transmitted STI and pretty much symptomless, but it can lead to infertility. Not that clever Ella wants a baby – she’s ambitious and that’s a great contraceptive.

She didn’t want to go to her GP for it to go on her record or talk to her parents, who have never mentioned sex. She asked me to stay while she got tested, and treatment if necessary, and pick up free condoms. She’s confident and aware. I am really impressed. At her age I would have been mortified in here. As it is, I feel a prickly heat in case I see someone I know. As a single mother with three children, my love-life has flat-lined.

The blonde nurse who calls Ella is bright and breezy with dazzling white teeth and red lipstick. The nurse chats about the weather; how she likes Ella’s cool skinny jeans and sky-high shoes. She makes us feel comfortable in seconds. The well-built doctor looks like he should be on a rugby pitch. While Ella is otherwise occupied, I ask him how it is for young people locally. “Hectic,” he says. “I wish they were as sensible as Ella. It’s carnage out there for teens. We have such hang-ups about sex and young people in this country. And older people too.”

He looks at me. I blush.

He adds: “I wish it was like Holland. Underage pregnancies and STIs are far more under control. When boy meets girl they get tested and sorted for contraception before sex. We don’t talk openly here. I am open with my patients. I had an STI at 18. If you have unprotected sex, it happens.”

I nod. I need to drum it into my own boys. The doctor asks me the killer question: “When do you think the riskiest time for sex is?”

I think all sex is risky but shrug my shoulders and say: “My sons are 16 and 15. They probably think about it all the time.”

He agrees: “Day and night. And the time they are most likely to have sex is between 3.30pm, after school, and before parents get in from work.

“We’ve had teenagers tell us they use crisp packets because they are too embarrassed to buy condoms or can’t afford them. We give out free contraception and sometimes money to get the bus home.”

I think of crisp packets’ burning saltiness and the terrible noise they must make. Surely that is more embarrassing than buying condoms? Not in the heat of the moment. I am glad I am always home at 3.30pm.

Ella taps me on the shoulder, smiling. She hasn’t got chlamydia. She takes home a free box of condoms in a plain white plastic bag. The doctor says to me: “Wait a minute.”

He returns with another plastic bag. Inside are four boxes with hundreds of condoms. Ella smirks as he says: “That should last you.” I blush from my neck to the roots of my hair.

Off we go. The two of us armed for any sexual encounter for the next decade.

When my boys, Ben and Aaron, return, I tell them where I’ve been.

“Weird job you have,” says Ben, looking in the biscuit cupboard, which is bare because they have been through it like locusts.

I clear out the kitchen draw. Aaron ignores the whole scene and asked what’s for dinner. “Pizza. Again,” I say as I tip a river of condoms in. They both say: “Ohhh, Mum!”

“Look,” I add, “these should last. I’m not encouraging you. This is sensible. You don’t have to buy them and you don’t have to worry.”

I don’t mention crisp packets.

A week goes by in a blizzard of work, cooking and domestic chores. All mine. We’ve heard nothing from Danny.

So, when I open the condom drawer and it’s virtually bare I do a double take. I close it and wonder where they’ve all gone? I’ve been home when they got back from school every day. Ben and Aaron return first; my younger daughter, Molly, is at an after-school club. She knows about the condoms but is uninterested and embarrassed.

I open the drawer and ask the boys: “Where are they?”

Ben raises his thick eyebrows and looks at Aaron who blushes the same way I do.

Ben says: “Mum, you helped Danny. And because of what’s happened you’ve done a great service to the community. The lads in my year are now protected. You have single-handedly prevented unwanted pregnancies and if there’s a dip in teen-births here next year it’s down to you.”

It’s the longest speech he’s made since puberty. I laugh until there are tears in my eyes.

• Names have been changed