Here is what I thought happened. I thought that as I tided my store room at the stables I put my car key in a boot for safe-keeping. I had been reorganising all the tons of horse stuff I have accumulated over the years, from rugs to bridles to brushes, numnahs, girths, lunge reigns, lead reigns, head collars, spray soaps, first-aid kits, boot polish, haynets, travel boots, exercise boots, tendon boots, over-reach boots, stable bandages, tail bandages, rosettes, buckets, scoops, fly masks …you get the picture. I was having a clear-out.

And afterwards, as I prepared to leave the yard, I had a crystal clear memory of looking into one of my walking boots, which had been standing on the side since I took them off to put on my long riding boots, and thinking, ‘Good, there’s my key, where I put it for safe-keeping.’ And picking up the walking boots, I went to the car.

The spaniel was sitting in the dog cage watching me. She saw everything but unfortunately cannot tell her side of the story. I thought I took the key out of the walking boot and, standing by the car boot, held it in my hand as I contemplated the state of the Volvo.

Now, the XC90 is not a pretty sight. The front passenger footwell is ‘the bin’, into which I throw empty drink bottles. The back seat is where I put all my jodhpurs and T-shirts along with packs of fizzy mineral water and the tyre inflator. The boot is mainly taken up by Cydney’s massive dog cage, around the sides of which I squeeze riding boots, riding hats, crops, dog leashes and various riding jackets.

This is London living, you understand. I have one small understairs cupboard at home and so the bulk of my tackle has to travel with me. The Volvo is a storage unit on wheels, the equivalent of what the Big Yellow would charge me £70 a month for.

So I was standing at the open boot looking at all this clobber, and, in my tidying mood, I made the mistake of picking up one jacket, refolding it and putting it back somewhere else.

The next thing I knew I was ripping the inside of the car to bits and starting again. With the key in my hand, or possibly a pocket, I began clearing out the rubbish, re-arranging the boots and shoes, rolling up dog towels and so on.

Twenty minutes later, hair standing on end, I straightened up and thought, ‘Jumping Jiminy! Where’s the key?’ It wasn’t in my hand, or my pocket, or handbag, or anywhere else I looked as I threw myself around in a frenzy. After half an hour searching, I ended up unpacking every single item from the car and laying it out on the grass as if this were a crime scene.

The other girls at the stable yard came out and did what they could to help but I was upside down, shining my iPhone between the seats and clawing at the carpet. At one point I found wedged in the seat rails a Snickers bar I’d bought three weeks before and lost after leaving it on top of a sweatshirt on the back seat.

‘There it is!’ I shouted in delight, getting everyone excited for a second until they realised I was munching a chocolate bar.

‘Ooh, this is nice,’ I said, as I buried myself back under the seats again.

An hour later, I was still at it. People were getting worried. Word got out. Phone calls were made. A key-finding collie called Eric was mustered and ordered to search. He sniffed excitedly and ran round in circles.

‘Are you sure you had it at the car?’ someone said. ‘Yes, yes,’ I insisted.

I called the RAC, only to be told my policy doesn’t cover lost keys. I sat on the grass and meditated. I knelt and prayed no fewer than three times to Saint Anthony and Saint Jude, which marked somewhat of a performance low on their part. Finally, I decided to call my mother. She said, ‘Go back into the stable yard and look at the last place you were.’

‘But I left with the key in my hand!’

‘I don’t care. Just do it. It will be there. It won’t be anywhere near where you think it is.’

‘How do you know?’

‘Trust me. I know.’

So I went back to my store room and stood staring. And quite a propos of nothing, I casually opened the drawer of a plastic storage unit and on the very top, put there for obvious safe-keeping, was the key. I rang my mother. I knew how she knew. ‘It’s the menopause, isn’t it?’

My mother sighed. ‘I didn’t like to say.’