Tomorrow marks the most competitive date in the primary school calendar – and I’m not talking about sports day.No, this is the one marking the end of the school year, when the nation’s mothers get one last chance to show their child’s teacher just how thoughtful, imaginative and generous they are.And, more importantly, when one ruthless school-run mum gets to send the others away for the summer with a powerful message: the position of playground Queen Bee has officially been filled.I’m talking about the kind of woman who agrees to a £5 gift limit, then turns up carrying a Jo Malone bag while their seven-year-old grapples with a florist’s bouquet so huge only their shoes are visible beneath it.I should know. Because I was that dreadful mother. I didn’t start off so cut-throat. At the end of my eldest daughter’s year in Reception, I spotted a mug bearing the words ‘World’s Best Teacher’ in a gift shop and thought: ‘That’ll do.’But it didn’t do at all.When we arrived at school on the final morning of term, I watched from the sidelines as far more seasoned mothers processed through the gates bearing gifts that, quite frankly, made me look and feel like an absolute cheapskate.One had her husband in tow, lugging an olive tree tied up with a silver bow. 'I learned never to underestimate the enemy. The end-of-year gift was not the sweet, informal gesture I had imagined. It was the final battle of the school year,' writes Rachel HalliwellOthers carried Selfridges bags and gift boxes from The White Company. Who knew what was inside them? But that wasn’t the point. The packaging suggested planning, expense and a level of sophistication I’d plainly failed to bring to the occasion.That was the day I learned never to underestimate the enemy. The end-of-year gift was not the sweet, informal gesture I had imagined. It was the final battle of the school year – and I had arrived armed with a piece of tat.A year later, I made sure there would be no repeat humiliation. My daughter excitedly asked when we were going shopping for her teacher’s present. The memory of the disappointment on her little face when I told her I’d already picked something up still haunts me.But at the time I felt justified in removing her from the process. After all, who in their right mind entrusts a small child with something as important as their position in the parental playground?I began modestly enough with artisan chocolates, but these soon gave way to luxury candles and small items of jewellery. The big problem I faced, though, was that I didn’t actually have the financial means required to win this contest.There were too many other mothers with far deeper pockets able to spend silly money.No matter how luxurious my candle, someone else could produce a cashmere scarf.However impressive my chocolates, another mother would arrive with champagne and theatre tickets.Clearly, I needed a different strategy. If I couldn’t outspend the competition, I’d out-think it by making my presents deeply personal. This was when matters progressed from competitive to unhinged.By then I had two of my three children in school and began sending them in like miniature undercover agents, instructed to find out what music their teachers listened to and what hobbies they enjoyed.They came up trumps.One teacher loved The Smiths, so I tracked down a vintage band T-shirt. At the time, I felt terribly clever, regaling the other mothers with stories about just how much detective work had gone into sourcing it.Looking back, I suspect the poor man opened it in the privacy of his own home and spent the rest of the summer wondering whether he needed a restraining order.There were gardening gloves for a teacher one daughter had noticed spent playground duty pulling weeds from a raised flower bed. Another mentioned holidaying in Cornwall, so I found a restaurant near the town where she stayed and bought her a cream tea voucher. Some mothers turn up carrying a Jo Malone bag while their seven-year-old grapples with a florist’s bouquet so huge only their shoes are visible beneath itAt one point, after discovering a teacher adored her dog, I considered commissioning a portrait of it. Thankfully, I came to my senses after a friend said that obtaining a photo of somebody’s spaniel (this was pre-social media) without their knowledge sounded like evidence in a stalking trial.My reign of terror was curtailed once we entered the secondary school years, where gifts for the teachers are no longer a thing. But no one told me, and by then I had an allotment and was keen to flag my Good Life credentials.So when I announced that I planned to assemble a hamper for my eldest girl’s Year 7 form tutor – homemade strawberry jam, courgette chutney, freshly cut flowers and perhaps a bottle of elderflower cordial – she looked at me as though I’d proposed running naked down the corridors. It would be social death for her either way.By the time my youngest daughter started school, 11 years after her oldest sister, the school she attended was getting wise to mothers’ Machiavellian tactics and set about to defang us. Individual gifts were replaced by a mandated class whip-round and one sensible joint present in order to eliminate showboating.It broke my competitive heart. After all, where’s the fun in that?