Enter the church of St James the Great in South Leigh and you suddenly find yourself in a place reminiscent of pre-Reformation England.

For the walls are covered with paintings that carry you back to the Middle Ages as if travelling on the back of the archangel St Michael — who is depicted here with his arms and legs covered in a feather outfit to match his wings. I was astonished by the bright medieval art gallery, but it soon became apparent why the place is not better known. A question hangs in the air: when does what one expert call ‘Restoration’ cross a line and become what another calls ‘Repainting’? I have pondered this at Roman villas in North Africa, where rebuilding appears to be under way. My guidebook Oxfordshire, edited by Arthur Mee and published in 1942, is unequivocal. It says of the South Leigh paintings: “The greatest treasure of the church is in its 14th- and 15th-century wall-paintings, happily rescued from coats of whitewash. In spite of long oblivion it was possible to restore them line by line, and the quality of the drawing and their wonderful escape make them famous in the story of such recoveries.” But after the war we all seem to have become more sceptical. Pevsner, in his Oxfordshire volume of Buildings of England, published in 1974, is almost dismissive. He writes of the paintings: “C15, mostly heavily restored in 1872 by Burlison and Grylls.” And the very good guide booklet for sale in the church, by Valerie Hirst, explains: “They have been restored many times, most recently in 1992. They are a dramatic and unique representation of an early church’s teaching to village people who were unable to read and write.” And that, surely, is the point. However ‘heavily restored’ the paintings in their present form might be, they provide an extraordinary insight into the medieval mindset — which must have been constantly influenced by church interiors like this. That St Michael, for example, depicts him weighing souls. The Virgin Mary intercedes on one side by dropping rosary beads into the scales, and devils try to haul them down on the other — a frightening story to an illiterate England. Roger Rosewell, in his book Medieval Wall Paintings, says: “An original painting of his scene may be seen below a later and larger Victorian over-painting made in 1872. An even more frightening picture shows the seven deadly sins spewing from the jaws of hell. South Leigh church was in the parish of Stanton Harcourt until 1869, and it was the first vicar of the separate parish, Gerard Moultrie, who discovered these murals beneath the whitewash. Back at Stanton Harcourt, though, is an extraordinary and direct connection to the battle which put the Tudors on the throne, and without which the Reformation may never have happened. For Robert Harcourt was the standard bearer of Henry Tudor, Earl of Richmond (later Henry VII. father of Henry VIII) who defeated Richard III at the battle of Bosworth Field in 1485. And over his tomb in Stanton Harcourt hangs a sad-looking piece of rag, which is all that remains of the standard that was the rallying point at the battle. According to Arthur Mee, the standard was in 1942 accompanied by a plumed helmet, but there was no sign of that when I visited last week. As for wall paintings at Stanton Harcourt, only a few splashes of colour remain.