There was no one about but a young man who was digging up the tulips and putting in bedding plants. He was very pink and white, bare to the waist of his muddy corduroy trousers and did not look as if gardening was his normal task. His clean-shaven, demure face and unsteady blue eyes suggested a curate attending to the vicarage garden. When I told him that I had heard that travellers could be put up for the night, he agreed fervently that they could. Yes, yes they could. Indeed they could. Someone would come out shortly to receive me. At the moment the management was in conference.

This unexpected echo from the commercial world amused me; it also suggested that here might be a commune efficiently run. A home-made bench of oak on the well-kept lawn faced the front door and there I sat waiting for the religion to turn up.

It came out, slender, tall and commanding. She looked just right for an abbess in spite of sweater and slacks, with large eyes and a full-lipped mouth in a serene oval face. She might, I thought, lack piety, but not discipline.

I introduced myself, explaining that I was on a walking tour of the tidal Severn and so had no more baggage than the small pack on my back. She was kind enough to say that I was just the sort of person they liked to entertain, and led me off to a recently built annexe, extending from the main house into the Forest, to show me the visitors’ accommodation.

It was simple: a white-washed cell with a comfortable bed, a table and an armchair. There were four or five other cells opening out of the passage, and at the end of it a fine, tiled washroom with showers and lavatories. She hoped I would join the community for supper. I should come along to the bar when I was ready.

I was glad to hear that there was a bar. The atmosphere of mixed simplicity and affluence puzzled me. It did not fit the pattern of a large farm which ran a guest house on the side. Monastic rule must come in somewhere. Indeed I might have dropped in at a medieval abbey famed for its hospitality. The handsome young abbess had mentioned no charge for bed and breakfast.

Having made myself as presentable as I could, I returned to the entrance hall of the main building. Double doors wide open gave me a sight of the refectory, arranged like a school or college hall with a high table and two short wings. Across the way was the so-called bar, which more resembled a small party in a country house with the host serving drinks from a white-clothed sideboard and his guests scattered about. The abbess, who had changed into a black robe with a curiously heavy gold brooch beneath one shoulder, came forward to greet me and led me to the dispenser of alcohol and wisdom.

‘This is my uncle, Simeon Marrin, and this is Major Denzil Matravers-Drummond, another of our guests.’

This first meeting with Marrin failed to give me any clear impression of the man. Tall and thin, but with chest and arms well developed, he could have been a somewhat ascetic clergyman in his forties who, say, had rowed for his college in youth. His grey eyes were large and far apart, like those of his niece though not as calm. Power, yes. I cannot be sure, but I think I sensed that. In any case it was not long before I did.

The major was of a very different species – older, preoccupied and with a nervous trick of raising his hand to pull at a moustache which no longer existed. One could hazard a guess that, like many retired military men, he was busy catching up with obscure intellectual interests – a likely type to fall for whatever Broom Lodgism was. The odd score of colonists sitting or standing about the room were mostly young men and women, healthy and attractive. But among them was a minority who fitted my expectations, satisfied with their own salvation and looking as if they had just returned from a psychiatrist who had successfully excised another piece of individual character. It seemed odd that all these were bald.

We trooped into supper. I had been placed between Simeon Marrin and his niece Elsa. On Marrin’s other side was the major who, I gathered, had visited Broom Lodge on several occasions. The rule seemed to be that one stiff drink or a sherry was permissible before the meal. At table one was offered a soft drink or a mug of cider or perry from the Severnside orchards.

‘How did you hear of us, Mr Colet?’ Marrin asked.

‘From the landlord of the inn at Blakeney.’ I told him how I had been walking down the left bank and up the right bank of the Severn Sea with a vague interest in Roman ports.

‘Are you an archaeologist?’ Elsa asked.

‘No, an economist specialising in ancient history. Archaeologists find and uncover the buildings. I want to know how the people who lived in them had enough to eat.’

‘Ah! Ancient agriculture, what!’ the major exclaimed. ‘Just the man for you, Simeon! Now, Mr Colet, tell us how the Egyptians could afford to take such a mass of labour off the land to build pyramids and still feed the people. What?’

Such an invitation to talk inevitably made me commit the crime of lecturing at dinner. I addressed myself mostly to Elsa, and not only from curiosity. When she was interested her face lit up and I realised for the first time that she was extremely attractive. As a concession to the formality of the evening meal she had let loose the ash-blonde hair which, when I first saw her, had been coiled in a severe bun.

So I replied that the major was right in supposing that one of my subjects was subsistence agriculture. For example, I could understand how such a commune as Broom Lodge just managed to feed its colonists, but I should be fascinated to learn how it produced surplus value, as it obviously did.

‘I will show you round tomorrow, Mr Colet,’ Marrin said.

The subject was promptly dropped. Elsa broke the respectful silence by asking about Roman ports on the Severn. I explained that on the east bank there were apparently none. If one were found it might suggest new aspects of the imperial economy: transport of slaves and rations for example. The ports on the west bank represented straightforward capitalism – mining of iron in the Forest of Dean and direct shipment to the Continent.

‘Some say gold, too,’ the major remarked. He bent forward across Marrin as if eagerly awaiting a reply.

‘A tradition with no truth in it,’ Marrin interrupted. ‘Geologically it is most unlikely. But that hasn’t stopped prospectors searching for it from time to time.’

I look back now at that first mention of gold. The thread of gold runs through the mysterious tapestry of Broom Lodge. I see it again and again appearing on the surface but still forming no recognisable or believable design.

My first impression of the colonists was that they were a hard-working bunch, starry-eyed or not, who knew the figures for profit and loss on their various enterprises but seemed vague about those for the whole commune. Pigs were the mainstay. Broom Lodge had ancient and extensive rights of common in the Forest, and the pigs were free to wander and stuff themselves with acorns in season. Superior flavour had won the colonists a London market for the products of the smoke-house. They were also breeding back to the wild boar since there was a demand, mostly from the Continent, for its meat.

However, the pigs, a flock of sheep – also benefiting from common rights – and a hundred acres of arable could not possibly give a return to keep some thirty men and women living in civilised comfort. By the time I was off to an early bed it was obvious to me that Simeon Marrin was subsidising the colony from income or capital. Why? The propagation of his gospel, whatever it was, had to be the answer.

In the morning, walking round the estate with him, I saw that his hospitality must be even more generous than I had supposed. The commune turned out to be a training centre, and the training was nothing like so efficient as the farming. We started off in the wheelwright’s shop, where two married couples were hard at work on wagon wheels and more delicate jobs for dog-carts and buggies. They must have had some practical lessons elsewhere but now were following drawings and diagrams. A finished wheel, though smartly painted and with professional slender spokes, was to my eyes very slightly oval.