A big, burly man, with a deep, slow voice, he is a quintessential English farmer, to whom growing crops and raising livestock are as natural as breathing. Now 69, he has devoted his life to the land, and though the current crisis is forcing him to adapt his methods, the idea of stopping has no place in his outlook.
Francis's family have been farmers for generations. Before the parliamentary enclosures of the 18th century, his ancestors on his mother's side reared huge numbers of horses on the Mendips, in Somerset. The animals were destined for transport work in London, and herds of them would be driven to the capital, up what is now the A4.
The forebears of Francis's father were established on the Cotswolds by 1860, and today he farms 600 acres, half owned, half rented. The operation - on a relatively small area - is still just viable because the farm is run as a family unit. His sons, Stephen and Simon, both work full time; his wife, Monica, takes in bed-and-breakfast guests.
Most of the land is high and cold - at least 700ft above sea-level - and some of it is too steep to cultivate, especially where the plateau falls away in undulating banks towards the escarpment above the Severn valley. All the fields have names, handed down over the centuries, and often they reflect the nature of the ground. "Clay Hill" speaks for itself, and so does "Stony Croft" - although this last scarcely does justice to the mysterious objects scattered about its surface.
The shallow soil is full of "brash" - pieces of limestone that have broken off the underlying rock - and in hundreds of the stones are embedded fossil skeletons of scallops and other sea creatures - which shows that these hills were once on the ocean floor, and must have been forced upwards millions of years ago by some gigantic upheaval of the Earth's crust.
On their better fields the Evanses grow wheat and barley, alternating with oil-seed rape, which breaks cycles of disease in the cereals.
Looking out over the winter wheat in the Thirty Acres, Francis can tell me exactly what every phase of cultivation has cost: ploughing, pounds 9 per acre; tilling (twice), pounds 2.70; drilling, pounds 6; seed, pounds 15. No fertiliser has gone on to the field yet, but an application in spring will cost pounds 11-pounds 12 an acre. Eventual harvesting will come to pounds 21 an acre and, if the weather is wet, drying the grain will cost anything up to pounds 9 per ton.
Yet by far the most expensive item will be the various sprays - herbicide for suppressing weeds, and fungicides to kill off diseases that would otherwise attach themselves to the growing crop. Taking all this into account, the field will have to yield more than three tons to the acre to make any margin above cost.
In the last four years the price of wheat has fallen drastically, from a peak of pounds 130 per ton to its present pounds 68, and one leading merchant is already quoting pounds 62 for next year's harvest. Paradoxically, in spite of this gloomy outlook, more people are going into cereals, as farmers forced out of dairying look round for a new alternative. The inevitable result will be a grain mountain next autumn. This year's harvest produced four million tons of wheat for export, but it looks as though next year's total will be at least six million - and that will push the price down further.
In the middle of these upheavals, Francis is adapting all the time. He has reduced the size of his sheep flock, but is converting some of his less productive arable land into grazing - for, in spite of all the scares about BSE, it is beef that has kept the farm going. The secret is that it runs a suckler herd - cows rearing their own calves - so that every animal's history is known and controlled.
Farmers, Francis reckons, "are going through a traumatic period of change". Yet he is sustained not only by natural optimism, but also by his deep knowledge of history; he knows that agricultural depressions are cyclical, and that many have come and gone before this one.
He points out that when the wool industry collapsed in the 1840s, hundreds of families left destitute in his area were shipped off to Canada and America, leaving their houses to fall down and disappear. In the great depression of the Thirties, 60 acres of land just west of his own holding were abandoned, and reverted to scrub. Now they are back in hand - but who knows if they may go wild again?
Luckily he has an extra string to his bow, in that he owns a considerable area of woodland and is a skilled forester. In the last 20 years many farmers have succumbed to temptation and sold their woods to professional firms which buy and manage on behalf of investors. Now Francis is more glad than ever that he has held on to his, as the trees produce steady income from thinnings, and go on growing whatever the economic climate.
The point about him is that, although officially retired, he never stops working. If he is not helping on the farm, he is in the woods or rebuilding collapsed sections of the dry-stone walls that bound the fields - a task which gives him huge satisfaction.
In his youth, when milking by hand, he spent hours leaning against cows' flanks, observing the patterns used by masons in the stonework of the barn. Now he re-creates those patterns in the walls, making sure that every junction between stones is covered by the one above. On a good day he can complete two linear yards - but, as he says, "the wall's got to be put up proper. If he's only going to last half a lifetime, it becomes an expensive exercise."