IT was an ordinary Saturday afternoon shopping trip when David McBeath realised he'd have to have that conversation with his 12-year-old daughter.
Not the birds and the bees chat - no, it was the can of worms with the large D on the front which had to be opened, all because Jacquie told him she could smell marijuana.
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"I was completely taken aback. I knew we'd have to talk about drugs at some point, but she was still at primary school for goodness sake, so I just wasn't expecting it," he says.
When parents face the difficult task of confronting their children about drugs, it can be an explosive time. Some get angry at the thought of their child getting hooked - even going so far as to ransack their child's room searching for bongs, rolling papers and cannabis. Others just clam up and refuse to discuss the topic.
But many will face awkward conversations which are likely to result in heated arguments and mutual resentment.
When 36-year-old MOT adviser David, from Boghall in West Lothian, first discovered that Jacquie knew about drugs, he was faced with a dilemma. She was just entering her last year at Howden St Andrew's primary school, and he admits he had never even considered that she was old enough to know what drugs were - let alone what they looked or smelled like.
"We were out shopping in Livingston and were having a nice afternoon buying clothes and chatting about what she'd been taught at primary school that week," he recalls. "Then she suddenly tells me she thought she could smell someone smoking marijuana. As soon as she said 'that smells like hash', I was completely taken aback.
"I thought: 'How am I going to deal with this?' and I knew it would be difficult without getting angry or upset.
"I always knew at some point we were going to have to have a talk about drugs but I thought that was still a few years away, because she was still at primary school.
"I started wondering whether she'd already taken drugs or if her friends had been offering them to her. My biggest worries when it comes to Jacquie have always been drugs and teenage pregnancy - they're the main fears for any parent. But I never expected to have a discussion about drugs when she was still 12.
"When I found out that the reason she knew was because a school friend's father smoked dope in his house when she had been round visiting, I was even more unsure of how to deal with what she was telling me."
While a lot of parents would no doubt throw a fit at such information, David says he didn't want to act hastily and instead he decided to contact the Scottish Executive's Know The Score campaign. And he was so impressed with their help, he agreed to appear in its latest TV ad campaign.
"I'd seen their adverts on billboards and thought that I needed to get as much information as I could before doing anything else. And when they sent one of their packs through the post, Jacquie and I sat down and went through it together," says David.
"Luckily, we're a very close family and we talk quite a lot anyway, so it wasn't as difficult as I thought. She started opening up to me about some of the things she'd experienced - such as her pal's dad smoking drugs - and I told her about some of the things I'd seen when I was younger and some of the people I knew who had taken drugs.
"We ended up having a really long chat about it and I was really relieved when she told me that she'd never taken drugs and had no intention of doing so. When she's older, I know she'll inevitably be offered drugs but I'm glad that she's now in a position where she knows all the facts and can make her own mind up about them. And her attitude has also made me think twice about banning her from her friend's house and so I still let her go round."
Thankfully, David and Jacquie's experience has been a success, but Know The Score says that there are countless families who have found it less easy to talk to each other about the dangers of drugs.
"The problem with parents is that they tend to just panic about it," explains the campaign's adviser Mhairi Frame. "They automatically assume that their children are taking drugs and they get angry or upset, but that really doesn't help anyone.
"We want them to calm down and have as much information as possible so they can make an informed decision about the problem and then sit down and talk with their child. A lot of the calls we get are from parents worried that their children may be smoking cannabis, but it's likely they'll just be at the stage where they're thinking about experimenting and won't have tried anything yet. We can send out information and advice about all kinds of different drugs, so the best thing to do in situations like this is to read everything and then decide how to approach the subject."
She adds: "Lots of parents and children want to discuss their feelings about issues like drugs but find it really difficult to do so. Teenagers in particular aren't keen to talk to their parents because they think they won't understand what they're going through. A lot of them expect their mum or dad to just hit the roof."
That didn't happen to Jacquie. "Thankfully, we didn't have a stand-off or anything like that," explains David. "But a lot of other people just can't talk to their kids about something like this and that's a real shame."
And Jacquie admits that the talk with her dad has made her even more determined to avoid drugs. "I don't want to ever take them," she says. "When dad and I talked about it and read the leaflets it made me realise how stupid you'd have to be to try them. My friend's dad does and it's just minging. He looks terrible and I don't understand why anyone would want to do that to themselves.
"When we've talked about drugs, it feels like we're doing it as friends rather than as if he's my dad. I've been able to explain how I feel about drugs, and that's been really good."
IF WORRIED PARENTS KNOW THE SCORE ON NARCOTICS AND THEIR EFFECTS THEY CAN GIVE THEIR CHILD THE RIGHT ADVICE
Q: If my son takes drug X will it lead to Y? This is generally applied to cannabis leading to harder drugs such as cocaine.
A: There is no strong evidence to support this theory and most young people who experiment with recreational drugs do not go on to become regular drug users.
Although a small minority of people who use "soft drugs" like cannabis will move on to other drugs, there will be many other factors behind this rather than a simple case of "I've tried cannabis let's move on to heroin".
Q: My son/daughter is acting strangely/moody/is in the wrong crowd... what can I do?
A: Think carefully as to why you think this may be related to drugs. It is vital that you talk to your child about any other potential problems they may be having and whether there are any other signs such as weight loss, spending money with nothing to show for it, etc.
Try to open the lines of communication and try not to be too harsh in your judgment, criticism or assumptions. Try to find out more about your son/daughter's interests, friends, and why they may be hanging around with that particular crowd.
Try to talk to them about their health and wellbeing. Learn more about the different types of drugs and their effects to ensure you are fully equipped to deal with a potential situation.
Q: My child tells me cannabis is harmless.
A: Find out the risks associated with cannabis and mental health issues. Although cannabis is not a physically addictive drug it can act as a trigger for any underlying mental health problem and can easily become a habit. Instead of helping you to relax, you may find you are anxious and agitated, your mood may be lower, concentration is harder and you may become paranoid.
Smoking cannabis can lead to respiratory disorders, coughs and sore throats with both long and short-term use and there is no safe level for smoking anything.
Cannabis can also affect a person's emotional wellbeing possibly linked to depression, motivation, mood swings, etc. The myth that cannabis is harmless is not true.
For more information call the Know the Score helpline on 0800 587 5879.