Throughout the 1920s and 1930s he was one of the Church’s great apologists both in the newspapers and in books, making his points with equal parts of wit, charity, and cogency. Several of his opponents joined the Church in their turn, not coerced or converted by him, but inspired by his example and with their difficulties removed.

  He was the Catholic Chaplain at Oxford from 1926 to 1939, where he equipped several generations of young men for the difficult transition from Catholic schools, where the faith was taken for granted, to the wider world, where it was met with indifference or outright hostility.

  He translated the entire Bible into English, both the Old and the New Testaments, in an heroic single-handed project undertaken at the request of the English Catholic bishops; but it is by his spiritual writings and by his apologetic and doctrinal works that he is most worthily remembered.

  Knox wears his learning lightly. He makes his points simply, with wit and humour. He attacks the fashion for dismembering the Gospels into a mess of different ‘Jesus-sayings’ from different sources by carrying out the same exercise on Boswell’s life of Johnson (the conclusion being that although Samuel Johnson had never existed, he should still be an inspiration to those who believed in him). To counter the fad for analysing the parables into a million structural pieces (and judging their authenticity thereby) he does exactly the same thing to the Sherlock Holmes stories, speculating about whether the inauthentic stories were the work of an interpolator or faked by a Dr Watson who had run out of genuine cases to report.

  In less scholarly fields he tailored his message according to the capacities of his hearers. In A Retreat for Lay People he compares people who have all the material of faith but somehow not faith itself to flies buzzing at a window-pane, and in The Mass in Slow Motion he tells his convent girls, too often encouraged to make up ‘spiritual bouquets’ of sufferings, penances and mortifications, that the bouquets he would like best would be made of ice creams and visits to the cinema.

  As a famous apologist and great communicator Knox was often asked to give sermons on feast days and special occasions, and the Liturgy of the Hours contains extracts from two of them, for St Edward the Confessor (13 October) and for St Philip Howard (19 October).

  In the earliest centuries all vestments were white – the white of baptismal purity and of the robes worn by the armies of the redeemed in the Apocalypse, washed white in the blood of the Lamb. As the Church grew secure enough to be able to plan her liturgy, she began to use colour so that our sense of sight could deepen our experience of the mysteries of salvation, just as incense recruits our sense of smell and music that of hearing. Over the centuries various schemes of colour for feasts and seasons were worked out, and it is only as late as the 19th century that they were harmonized into their present form.