Felix is familiar with substitutes.

Any Saturday morning on his little football field sees a couple of hopefuls warming up on the sidelines, waiting for the moment a player is taken off, and they are sent on for their big chance to make a difference in the game.

And he is just getting his first lesson in literary substitutes, courtesy of CS Lewis.

The Horse And His Boy is the story of what happened during the reign of High King Peter, Queen Susan, King Edmund and Queen Lucy, in a land called Narnia, at a time which happened only in a writer’s philosophy.

By pure accident, we have stumbled on a tale which is quintessentially boyish. Its hero is Shasta, a little peasant boy who lives in Calormen with his father the fisherman and is used as slave labour to run the meagre business.

If the world of Narnia has a Middle East, Calormen is it: Shasta’s father’s skin is coloured accordingly, but the little boy has pale Narnian skin and it becomes clear very early on that he belongs somewhere else. After meeting a Narnian horse and staging an escape he is mistaken for a prince allied to Narnia in the streets of the capital city.

Of course the real prince, Corin, returns. They meet: and they like each other instantly.

What is riveting for Felix, as he reads, is the simple straightforward characterisation of these two boys, worlds apart and yet sharing a common place: childhood. Felix says he loves the book, firstly because it is a travel book with a map one can follow, visiting exotic places we can only dream of; and secondly, because the attitude of the boys is so like his own.

CS Lewis treats the relationship between the two with a lucid simplicity. One is poor, the other rich, but neither resents the other. They have an instant uncomplicated loyalty to each other; but no-one thinks of changing places.

Status is a funny old thing. Other authors have used confusion over someone’s standing to tell a tale. It is an old, old ploy: to use beggar’s weeds to clothe a king and watch the reaction of those around him.

Charlotte M Yonge made it, just, into the twentieth century, dying in May 1901 at the ripe old age of 78. She was a prolific English writer whose work does not often find its way into print these days: but today we have need of her, because she points the way to someone else.

A novelist associated with the Oxford movement, she wrote 160 works all told: and often used the considerable proceeds to help with charitable and missionary causes. She was founder and editor of The Monthly Packet, a magazine aimed initially at young Anglican girls.

It was in The Monthly Packet, beginning in December 1865, that a story was serialised: it was called The Prince and The Page.

It concerned ancient English rivalries at the time of Prince Edward, later to become King Edward I: at the Battle of Evesham he vanquished his enemies the De Montforts, but one, Henry, was left for dead on the battlefield. As the plot weaves its way onwards, it seems this last unfortunate survived and lived his life disguised as a beggar.

The King discovered his identity and pleaded with him to return to court, but to no avail.

He had a beautiful daughter whom no-one would marry because of her humble birth: and finally , a true suitor appeared who would marry her, and thus passed the beggar’s test.

So it appeared this man of high birth chose to cloak his identity not for his own safety: but to test the motives of those who sought his trust. Clever.

It happened that a pair of American eyes lit on this story written by a prim Anglican Victorian novelist. And they sparked a tale which delved much more deeply into the business of authenticity and loyalty.

Mark Twain read it, and the germ of an idea began to grow. He would have a prince and a pauper swap their lives, so that each could see how the other half lived. It is said Twain had favoured Edward VII – the Prince of Wales at the time – for his tale: but it was hard to lose the prince in the slums of the day. It would not seem credible.

Instead, he chose another time. He wrote to a friend: “Did I ever tell you the plot of it? It begins at 9 A.M., January 27, 1547 . . . . My idea is to afford a realizing sense of the exceeding severity of the laws of that day by inflicting some of their penalties upon the king himself, and allowing him a chance to see the rest of them applied to others.”

Twain’s lesson is a resounding one. His writing is vivid and universal: it might, somehow, take place in any time. I have always loved this story of Henry VIII’s son, Edward Tudor, who swaps with pauper Tom Canty, of the humbly named Offal Court, in the great and well-ordered city of London.

The tale’s lessons are universal: the impotence of the King becomes quickly clear as he is immersed in the underworld back streets, with all their sordid merciless undercurrents. In the end it really is only through experiencing what it is like to be the lowliest of his subjects that Edward becomes, even for a short time, an effective monarch.

Of course, Twain meant it to be read beyond its simple meaning. It had so much to say to the nineteenth century. The lawmakers, insisted Twain between the lines, should always stay in touch with the common man who carried the brunt of such legislature.

Swaps like this depend on like minds. The simple trust between the boy-prince of  Archenland and the fleeing fisherman’s son was true as steel.

Some, like Henry De Montfort, choose to cloak their identity to test the honour of those who approach them: status can encourage false loyalty which would not stand the test of time.

Little did Twain’s Edward know how his swap would play out: the scales fell from his eyes and he saw the world from an entirely new and more real perspective. More than this: he acted upon his findings. And in doing so he became a more trustworthy monarch.

Let us hope those in charge of our own legislature have as much curiosity, bravery and integrity.