‘I’d assumed they’d be chanting or singing,’ I said, surprised at how quiet it was.

‘Oh, we will be,’ Samantha said. ‘That comes later, once we’re inside. Don’t want to alert the pigs to what we’re planning – we need the element of surprise.’

‘What are we planning?’ I asked nervously. This was getting serious.

A ripple of excitement went around as the first ladder was propped against the fence, thick blankets flung over the barbed wire, and a second ladder passed up and over by three overgrown teddy bears.

‘Here we go,’ whispered Samantha, and to my surprise she took my hand. ‘Stick with me, OK?’

Sandrine rolled her eyes. ‘Catch you later,’ she said, vanishing into the crowd. ‘Not in the mood for this today.’

‘Oh that one, she’s such a misery guts!’ Samantha said, her eyes shining. ‘This is the fun part – come on!’

I’d have preferred to go through rather than over the fence, but as we got closer, Samantha suddenly shoved me towards the foot of the ladder. She was ripping my backpack off my shoulders. ‘Leave that here, you can come back for it. It’ll be fine,’ she said, and before I knew it, her hands were pushing my furry backside up the ladder. ‘I’ll be right behind you!’

Then I was at the top, straddling the barbed-wire fence. I could see for miles, wisps of smoke above the treetops to my left, rising from dozens of campfires and merging with the pinkening dusky clouds. To my right, the alien green mounds of the silos.

I froze, suddenly convinced I’d fall, but the encouraging faces of the women already inside were urging me over, their arms outstretched. Other women were pouring through the gap in the cut fence, racing towards the silos.

‘Come on, honey, almost there,’ said Samantha, halfway up the ladder behind me. There was a queue behind her. I couldn’t hold them up. No going back now.

Taking a deep breath, I put my hands flat on the scratchy blankets, slid my right leg down to the top of the second ladder, and swung my left leg round to join it. I was over! I half climbed, half slid the rest of the way to the ground, my knees trembling with fear and exhilaration. I had never done anything illegal before. I had to banish the vision of my disappointed parents and my furious headmistress.

Seconds later, Samantha was next to me. ‘We’re IN!’ She hissed, grabbing my hand again. ‘Man, what a buzz!’ Dragging me with her, she ran towards the silos, following the other bears, several of whom were already at the top of the grassy banks, dancing and hooting, chanting and singing.