Welcome to Britain, where the summer season brings out our national fibre, as unlovely and unwelcome as a bowl of stale All-Bran.

A while ago, I took off with the kids for seven days in rainy Cornwall; at Paddington, the train was already packed. Our group consisted of myself (five months pregnant), offspring aged six, four and 18 months, our nanny, a car seat, a buggy, a violin, a computer and six bags. Seven, if you count the picnic. Boarding was a squash; I had only been able to reserve three seats, as children under five don’t qualify for reservations.

As we were travelling on a Friday morning in Britain, we were naturally sharing the carriage with 13 men bound for a stag weekend, and to my relief the pre-nuptial blokes were very happy to give us a couple of their seats. They had bigger things to occupy themselves with, namely drinking industrial amounts of Foster’s and tormenting the groom, who was dressed as a giant baby in a pink velour one-piece with matching bonnet.

As we were approaching Swindon, Groom-Baby was playing peekaboo with the little one, who was squealing with delight, while Best Man was describing the programme for the next 48 hours (drinking, surfing, drinking and visiting a lap-dancing club). The other children were being normal, by which I mean there was quiet study of a dot-to-dot book interspersed by loud bouts of pinching and squawking.

At which juncture, a professional-looking woman came stamping up the carriage. I must assume she had no children, because her reaction was so over the top. “If you cannot keep your baby quiet,” she yelled, hair slides trembling with rage, “we will all have a VERY long journey indeed! It’s just so SELFISH!” I cowered as she turned on her heel. “Stupid old bag!” shouted Groom-Baby. I murmured rapid apologies for any disturbance caused. “We’ve all got kids,” he said. “Yours are no problem.” The journey continued. Every time the noise from our table threatened to waft down the carriage, I panicked. Yet short of strapping each child into a straitjacket and gag, there was no way I could transform them from small people enjoying throwing Frubes around into large people enjoying anagrams in The Puzzler.

Meanwhile, the stag party got louder. Songs were sung. Photos were taken with mobile phones. At no point, however, were eyebrows in any part of the carriage raised. The British don’t seem to care about men behaving badly. It’s babies behaving badly we can’t stand.

And I hate to point it out, but it’s always women who complain the most. Forget maternal instinct. There is nothing so basic as the instinct of a (presumably) single woman against that of another with children. Furthermore, presenting yourself not only as a multiple mother but also pregnant (What? Again?) merely adds to the anti-maternal rage.

We trundled on beside the Devon coast, the children chorusing: “I can see the sea!” At which point, another delightful soul came on down to join the fun. “You have been outrageous!” said she. “Your children have been shouting and screaming for the entire journey! (Untrue.) You have done nothing to shut them up. (Again, not quite correct.) Furthermore, you insisted everyone moved around the carriage JUST TO SUIT YOU!” The stag party went quiet. She glared at the nippers. She glared at my pregnant belly. “You are so smug! You are self-satisfied! You, you are so . . . so HOME COUNTIES!” she spat, storming back up to her seat. Wow. It had it all. Intolerance of children, intragender hatred, pregnancy envy, plus a bit of good old-fashioned class war. Our Australian nanny was mystified by this classic British moment. “Where are the home counties?” she asked.

“You are home counties!” shouted my four-year-old.

“Ho’ cowteez,” lisped the baby.

The stag weekenders laughed and laughed. “What is her problem?” they shouted.

I know: I should have hung my head and scuttled along to the hideously entitled “family carriage” where anyone in a nappy is conventionally banished, along with the trash, and lines of people waiting to be served in the buffet section. But I had reserved seats, and they didn’t happen to be in the family carriage. And anyway, how could a train full of blokes on the beer ever resemble an oasis of peace? The truth is that the British are allergic to the sight or sound of anyone under 10.