DESPITE THE NATIONAL Gallery’s insistence that kids are interested only in Rousseau’s Tiger in a Storm, children can and do fall in love with high art as soon as they can understand a story.

Titian’s Perseus diving headfirst into the sea to kill the monster, Uccello’s fabulous St George, Stubbs’s rearing Whistlejacket and Turner’s fiery The Fighting ‘Temeraire’ are all thrilling to infants over 3. This month, exhibitions of Velázquez and Holbein opened in London. Each is wonderful for children of 10 and over, as long as you bother to look at some books with them beforehand.

Holbein’s startlingly vivid portraits at Tate Britain will fascinate any student of the Tudors, but it is Velázquez at the National Gallery who may interest them more, thanks to an unsung hero of picture books. For 17 years, the author and painter James Mayhew has introduced children of 3-plus to works by Monet, van Gogh, Picasso, Degas, Leonardo da Vinci and many more through the agency of his mischievous Katie, who can enter famous paintings, causing havoc while Grandma snoozes.

Mayhew’s lively pastiches are a lovely way to start a lifetime of enjoying art: if you want to know what made Mona Lisa laugh, ask Katie.

In Katie and the Spanish Princess, our heroine encounters a Velázquez portrait of the Infanta Margarita, a luminous blonde child in a stiff golden dress. The little girls become friends, and Katie swaps her red coat and jeans for the Infanta’s costume. Enjoying the contrast, the two little girls visit Goya’s little boy with a magpie, and he, too, comes alive. The magpie flies out, snatches a jewel from the Infanta’s dress, and is lost. As the children chase the bird from painting to painting they chat to peasants by Murillo, before being told off by the Princess’s father, (one of Velázquez’s portraits of Philip lV).

A number of children’s authors, from John Masefield to J. K. Rowling, have imagined what it would be like if people in portraits could magically step out of or move about inside them. Posy Simmonds had a similar idea in the lovely Lulu and the Flying Babies but failed to use real paintings, like Mayhew; I’d have liked the whole book to focus on Velázquez, but once you get the idea you could spin a story around the Spanish royal children and the dwarf, like Oscar Wilde. Older children, of 9 and above, will get much more out of Elizabeth Borton de Trevino’s profoundly moving historical novel about Velázquez’s black slave, I Juan de Pareja (Farrar Straus & Giroux, £3.99); its absence from the exhibition shop is almost as sore a lack as that of child-friendly 100 piece jigsaws at the National Gallery itself.

For toddlers and nursery-age children, Lucy Micklethwait’s classic A Child’s Book of Art (Dorling Kindersley, £10.99, offer £9.89) is an essential for any family planning on visiting art galleries. It is supremely appealing and spans paintings from oriental miniatures to Hockney. Micklethwait organises paintings by focusing on small details (animals, colours, faces, shapes, numbers) in a way that captivates infants. Culture is seen as elitist only because so few people bother to teach it in a way that is accessible. If my children were able to grasp the miracle of Velázquez’s eggs or the moral intelligence laying bare Holbein’s sitters over half-term, it’s because they had such simple, splendid books to prepare them.

Far from being inaccessible, Old Masters are made for young minds.

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