Early in the Second World War, pacifist Roy Ridgway was asked by a policeman what he would do if he were approached by a German parachutist. He replied: “I would offer him a cup of tea.”

This was a magnificently British response to a peculiarly British ­situation. Britain had more conscientious objectors than any other comparable nation. That was largely because Britain was almost alone in recognising that such a thing existed. In France, military duty was an essential element of citizenship. In Germany and Russia, a refusal to take up arms on moral grounds was likely to get you at least imprisoned and possibly shot. Even in America, the land of the free, exemption largely depended on membership of an uncompromisingly pacifist church.

Britain’s geography and history had spared it the need for large standing armies, and national ­service was not part of normal life. Freedom of conscience was also (at least notionally) accepted as a fundamental right. So it was that the refusal of military duties on a variety of grounds was enshrined in law – although some contribution to the war effort was still expected – and staunchly defended from the top, with Winston Churchill declaring that this was “a definite part of British policy. Anything in the nature of persecution, victimisation or man-hunting is odious to the British people.”

In his excellent book, Tobias Kelly has focused on a handful of the 60,000 Britons who refused military service, using their experiences to light up the broader story of what happens when conscience collides with the imperatives of national survival. They are a well-chosen crew, each of whose lives might make a good Ken Loach movie.

Ridgway was a young working-class Londoner plagued by delicate nerves. Stella St John was an upper- middle-class young woman with a St Francis-like devotion to animals and the poor. Fred Urquhart was the Edinburgh-born son of a chauffeur, unabashedly gay and convinced of his outstanding literary powers. Ronald Duncan combined reverence for Gandhi with a masterful attitude to women. They had little in common, but they shared an extraordinary determination to stand up to authority and peer pressure in defence of their principles.