A text from the GP surgery invites me to complete an online questionnaire including my blood pressure. “Please contact us if you don’t have a blood pressure monitor at home,” it says, “so we can arrange an appointment.”

It is one of several overtures I have had from the NHS this year – because of my age, I assume – but I am stung by the implication that a home without a blood pressure monitor is incomplete.

The drawer where we keep medical supplies is, in fact, poorly stocked: it contains a few face masks, some loose plasters and a half-used blister pack of throat pastilles. Most of the actual medicine in the drawer is for dogs.

The next time I’m out shopping for a particular sort of glue, I wander down the wrong aisle and come across a blood pressure monitor. It costs £28, which seems a lot for an impulse purchase, and not enough for a blood pressure monitor.

“What’s this?” says my wife, pulling it out of the shopping bag.

“A blood pressure monitor,” I say. “All the best people have them.”

I don’t even take it out of its box; I shove it in the drawer with the plasters and dog pills, where it brings me less peace of mind than I’d hoped.

A week later I get another text telling me I have one day left to complete my health questionnaire. After lunch I sit at the kitchen table with my laptop and the blood pressure monitor. Following the instructions, I wrap the collar round my left arm and press start. Without warning the collar start to inflate.

“Whoa!” I shout. The collar keeps inflating, then subsides. Then the machine beeps and displays a reading. I Google it.

“But that’s high!” I say.

“What is?” says the middle one, walking in.

“I’m not sending that,” I say. “They’ll hospitalise me.”

“What are you trying to do?” he says.

“How can I make my blood pressure normal in a hurry?” I say. He looks up my question on his phone.

“Avoid caffeine,” he says.

“Too late,” I say.

‘It’s supposed to be lower in the afternoon,” he says.

“It is afternoon,” I say.

“How many times are you gonna test yourself?” he says.

“Until I get some numbers I’m happy with,” I say. “Just tell me what normal is, and I’ll work toward it.”

Eventually, after a bit of controlled breathing, I enter the lowest three readings of six and press Submit. I receive an instant reply. “Your answers will not be seen immediately,” it says.

Several weeks later I am offered an appointment at the surgery for a routine health check. I plan to walk, because the surgery is only about a mile away, and because once, when it was raining, I drove there and got stuck in traffic. In the end I had to pull over and run the final half mile. My pulse was comfortably over 100 when they took it.

On the day of the appointment it is raining again. I find an umbrella, but when I check the appointment time on my phone I realise it’s 15 minutes earlier than I’d written down. I drop the umbrella and get in the car.

Three-quarters of the way to the surgery I run into an intractable snarl behind a set of temporary lights, where the road is being dug up. There is no place to pull over and run. My chest starts to feel as if there’s an inflating collar around it.

At the last minute I sail into a parking space outside the surgery. After a 10-minute wait I am ushered in to see the nurse. My pulse and my blood pressure are unremarkable. I think: there is no machine I can’t fool.

Driving home, supremely relaxed, I find myself at the head of the queue behind the temporary light. A minute goes by. Then two. Then four. It becomes clear that the light is never going to turn green, although steady pulses of traffic are still coming the other way. The men who were working on the road have gone home for the day. A queue of about 20 cars is looking to me for leadership. Good luck with that, I think.

After about eight minutes an impatient motorist pulls out from behind me and zips down the single lane ahead. Ten cars follow him. Halfway along they meet a bus coming the other way. The jam spreads like a spider’s web, in every direction.

I am sealed in my spot, unable to even turn around, possibly for ever. My pulse, when I check it, is a steady 78.