While we await the toxicology reports from Madeleine McCann’s hair to show whether she was sedated the night she disappeared, people like me have a special interest in the results. As a mother of baby twins with a four-year-old son, I was guilty of dosing my child up for travel, and was surprised at quite how easy it was to get a doctor’s prescription.

So many tired parents of twins have done the same in the past – given their daughter a spoonful of “medicine” to keep him or her sleeping when they most needed it. If parents turn to Calpol (paracetamol pain relief), is there really such a leap to using the bottle of Medised (paracetamol with a mild antihistamine) instead, which sits on the same shelf in Boots?

Before I joined an evening out with mothers of the local Wandsworth twins’ club, I was a virgin to the pharmaceutical names of sedatives. There, after a few glasses of wine, the subject of drugging toddlers to travel came up, and the stories began to flow.

Around the table, the normally reserved mothers were holding forth about the relative merits of Piriton versus Phenergan. “I always dose them up with Piriton before a long car journey”, slurred one mother – “it’s great stuff, sends ‘em off to sleep in ten minutes”. She offered to spell it for another mother who got out her diary. “Phenergan’s just as good” suggested someone from the other side of the table. “It’s been around for years. Your mother probably used to give it to you” (She did, I found out later).

First, let’s make one thing clear. Mothers of twins are mothers in extremis, always looking for ways to cope with the constant pressure of two or more small children demanding the same thing at the same time. The behaviour of twin mothers, who generally have less time and less sleep, may not mimic that of singleton parents.

Stress and sleep deprivation can turn quite ordinary people into angry monsters, so isn’t the occasional spoonful of something to knock the little darlings out worth it just once in a while? We had tried flying all three children to Morrocco on a night flight earlier that year, with all the fretting and crying that the disrupted sleep routine brings, so could the alternative really be so wrong? As a fiftysomething American remarked to a shocked new mother, who had a crying baby most of the flight, “Don’t you give your baby something to keep it quiet if you are travelling?”

We were planning a long-haul trip to New Mexico, so I asked if the other mothers of the twins club had ever used sedatives for long haul. “Vallergan is my drug of choice”, piped up a frequent-flyer. She told me the alarming story of how she had given a spoon to her two children flying back from the Carribean. “They slept for a full 14 hours - including the transfer through Miami airport”, she relayed nonchanlantly.

“They finally woke up in the car on the drive to the house, they were so completely zonked that I did begin to worry that they weren’t ever going to wake,“ she admitted. The frequent flyer had got a doctor’s prescription for “travel sickness and jet lag” easily, and recommended that I do the same. The doctor asked no questions when I mumbled about “jet lag” for my four-year-old and handed over the prescription.

We were flying with my elder child only, so, on the day of the flight, I gave him a dose before boarding, my heart thumping. My husband and I sat back in our seats, and waited for peace to descend. It never came. Instead, our normally inquisitive four-year-old became unusually alert - throwing crayons around, snapping books shut, emptying raisin cartons on our laps and switching lights and blowers on above our heads. We waited for the sedative to take effect, as he discovered the bouncy trampoline qualities of the seat tables, annoying everyone around us. His energy refused to dwindle as the hours wore on.

When the stewardess announced there would be an unscheduled stop in JFK to refuel, adding another two hours to our journey inside the plane, I began to feel claustrophobic. It was now approaching midnight at home, he had normally been asleep for five hours by now, but still he wasn’t tired.

As my husband and I passed him backwards and forwards between us like a basketball, we realised that our plan to drug him had backfired. The small contra-indication saying “may cause agitation and insomnia” had been read too quickly – and never mentioned by the doctor who gave the prescription.

We never read the small print. And boy did we pay the price. After 12 hours on the plane, with no sleep for any of us, we reached our destination a complete wreck. It was, and still is, the worst flight in my living memory, and we had only ourselves to blame.