One look at Grace when I went to get her in from the field, and I knew she had eaten herself to the verge of oblivion.

Leaving the horses kicking their heels up in the field, while we went to France for a break from them, was always going to have mixed results. This is because, like Jack Sprat and his wife, one eats too much while the other eats too little. While Darcy the thoroughbred picks daintily at the grass, the pony is as greedy as Mr Creosote in Monty Python. I have known Gracie to eat so much she has burped. And horses, it is well known, cannot burp. It is physiologically impossible. I have thought about ringing David Attenborough and telling him I have the world’s only belching pony. He wouldn’t believe it unless he witnessed it. She opens the side of her mouth like a lager lout and goes, ‘Urrrrrrrrrrp!’

And yes, I know most horses gorge themselves on grass to an extent at this time of year, but truly, Gracie is something else. She is a compulsive over-eater who needs to be on a 12-step programme. She should go to meetings and say, ‘My name is Grace and I’m a grassoholic.’ In an ideal world, she would get a sponsor and not colic herself, one day at a time.

In reality, she pigged herself from dawn until dusk, and all through the night in all likelihood, for the entire ten days we were away. And unlike Darcy, who will have walked regularly to the water trough to drink and hydrate, Gracie will have refused to waste precious minutes journeying a few yards to the trough when those were minutes she could be spending stuffing her face.

When I went to get them in, they were stood together in the shade, swishing their tails. Darcy looked happily replete but as slender as ever. Gracie, on the other hand, was so fat and bloated she looked like she couldn’t move even to reach one more wafer-thin blade of grass.

And when I put a headcollar on and tried to move her, I had to pull for several minutes to get her out of parking mode then haul her to the gate, step by step. She stood in her stable blinking dazedly and lifting her tail up and down as if trying to pass wind. Sorry, this is not the column for you if you’re fazed by gastrointestinal reality. Every few seconds she would shift her weight from one back hoof to the other, as if she was foot sore. All the other girls at the stable yard gasped, ‘Oh no! She’s got laminitis!’ I told them, ‘Actually, she’s constipated.’

No one believed me, of course. Why would they? All logic would dictate that a horse shifting from foot to foot, so lame it can’t move, is a horse in the throes of laminitis. I did call the vet, though, because while I was fairly sure Grace was not in mortal danger of rotating pedal bones, she could well be in mortal danger of busting a gut, through overeating and failing to drink. Also, it was just before 5 p.m. on a Friday and I know Rule One of horse illness. If you need the vet, it is always out of hours. So I decided to get in before the cut-off.

She arrived promptly, confirmed she would not be charging triple time as I had made the call before closing, and slid on her rubber glove.

Those of a sensitive disposition look away now. ‘There’s a lot of gas in here,’ she said. ‘No blockage that I can feel. No twist. Not a bad colic. Just a lot of gas and…’ She rummaged away and effected a solution.

When she’d finished, Gracie looked much happier. But she was still lifting her back legs in the air and her sides were still heaving. So we sat up all night with her, venturing out only to get chicken kebabs. The builder unwrapped his to declare disgustedly that while I had chicken, he had got the wrong one. Falafel. He was so hungry he ate it anyway. An hour later, his face took on a strained look. He started to hobble. Then he declared he could not move. He shifted his weight. He blinked in pain. If he had had a tail he would have lifted it. Then he revealed himself to be full of gas. ‘Good god! You’re colicking!’ I said. ‘It’s that falafel,’ he groaned. ‘It’s expanding. How can vegetarians eat that stuff? No wonder they’re all so miserable.’ Three days later and Gracie is fine. The builder, however, is still hobbling about as lame as an old mule. I am thinking of calling the vet out.