Can it be that the one single agreeable thing about getting old is that one loses one’s pot paranoia? No.

I thought I was going to get away with it, but here it came again like a creeping fog: the terrible introspection, the loss of identity, the psychic disintegration, the paranoid delusions. And here already, I noted, was the paralysing delusion that I am rooted to the spot and somehow tied to the company by a bond of loyalty, to the extent that even to uncross my legs and leave the beer-garden table would feel like a terrible betrayal. It’s horrible. I hate it.

My immediate task was to try to drink off the paranoia or the evening would be over before it started. Trev was pulling belated, nauseated faces about there being too little or no vodka in his vodka and lemonade. It was supposed to be a double. Canvassing opinion, he gave his glass first to me. I could taste liquefied sweetener with a slice of lemon and nothing else. Here was my chance to pull myself out of this mire, extract myself from the magic circle, and try to retrieve my sense of self before it was chaff in the wind.

I uncrossed my legs, stood up, and — nobody seemed to mind — I went inside to buy a round. The bar was filling rapidly. The pub was small and cosy with a culture of conversation. From a small speaker above my head, the voice and guitar of Muddy Waters competed gently with the murmur of conversation. The bar staff were busy, and looked glad to be doing something at last. I had to stand and wait to be served for what seemed like an eternity.

My usual pot paranoia identity crisis was deepening by the second. If, as some say, the self is ultimately a holding action between competing factions, mine had now gone out for the evening, and the competing factions had decided to throw a party to celebrate, advertised it on Facebook, and 5,000 revellers had turned up and were causing mayhem. And if, as others claim, the self is little more than a social performance, a public role played with lesser or greater competence, I’d got stage fright. I was paralysed. I’d forgotten my lines and forgotten which part I was meant to be playing. I’d even forgotten which play I was in.

I stared at the other customers. This one looked like a collaboration between Alan Ayckbourn and Ionesco. And everyone in the bar was acting their socks off.

The delusions began; the usual delusions; my ordinary neuroses writ large, I think. An unshakable conviction, for example, that these confident, consummate actors gathered here in the bar were operating on a higher plane of consciousness than I was, and that they knew something of crucial importance, perhaps about me, that I cannot imagine nor will ever be permitted to know.

There was not one person in the bar who wasn’t engaged in conversation. And yet were not some of these conversations a little studied, I wondered, like those seen over the shoulders of the soap stars in the Rovers Return? I was under furtive scrutiny, there was no doubt about it.

Two could play at that game. I ostentatiously looked through, around, over people: never directly at them. For the benefit of my secret observers, I leant a jaunty elbow on the bar, crossed my legs at the ankles and looked patiently bored (lounge lizard Jeremy). I bent down and affectionately patted the solid flanks of the pub bulldog (Jeremy aka St Francis of Assisi). The dog gave me an offended look and waddled off. I made a great show of studying with fascinated interest the minimalist cartoon of Big Ben on a beer mat (contemporary art connoisseur Jeremy). I checked my iPhone (popular Jeremy) and reread this month’s phone bill. I turned and gazed with exaggerated fascination at the glamorous kaleidoscope of glass and mirrors, lights and coloured liquids behind the bar (delightfully childlike Jeremy).

And now the accusations started. I’ve been ham acting like this all my life. I am a man without a convincing character of his own. A fake. Not once in the past ten years have I ever told the truth for the truth’s sake, without calculating the capital that came with it. Not once have I laughed an innocent laugh. I was ugly yet vain, cretinous yet complex. A shirker. An alcoholic. A failure. My existence on earth could be summed up by the single image of a man bent over a bin scraping furiously at a blackened piece of toast with a knife.

‘Can I help?’ At last, the cheerful face of a bar woman. A mask, of course. But a bloody good one. ‘Six Jägerbombs, please, love,’ I said. ‘And a tray.’