IN a dimly-lit room in the Palazzo Strozzi, in the heart of Florence, stands a glass case. If you can wriggle through the crowd to get a glimpse, inside is a captivating terracotta sculpture of the Madonna and Child. Several things about this piece are remarkable. Since 1858 it has been held in the Victoria & Albert Museum in London, attributed to the sculptor Antonio Rossellino. This year, however, experts pronounced that it is in fact the only existing sculpture by Leonardo da Vinci. As such, it forms the centrepiece of a magnificent exhibition devoted to Leonardo’s master, Andrea del Verrocchio.

Known as The Virgin with the Laughing Child, and about 18 inches high, it was made around 1472, when Leonardo was a young apprentice in Verrocchio’s workshop in Florence. Galleries, and indeed this very exhibition, are stuffed to the rafters with paintings and sculptures of the Madonna and Child. You can’t help feeling artists must have grown as weary of this subject as of the Crucifixion and the Last Supper. But, since the Church was their main source of income, these iconic images proliferated. Naturally, the finest artists, like Verrocchio, Filippo Lippi and Raphael, took this image and transformed it into a profound portrait of their times, pushing the art form to its limits.

Clearly Leonardo also stretched himself from the outset. The baby in the Virgin Mary’s lap is chortling, gurgling so realistically you want to laugh with him. His mother, too, looks quietly amused, her mouth reminiscent of the Mona Lisa’s enigmatic smile. Verrocchio’s influence is apparent in this cheery representation, since his sculptures of cherubs and children were often merry. But for Leonardo to portray the Christ child like this was positively revolutionary. This image would have been viewed by some as heretical; in the 15th century, that was not a charge anyone who hoped for a long and productive life wished to have pinned to them.

This gem, by one of the greatest geniuses who ever lived, is a reminder of the early days of Florence’s influence and power. Leonardo was one of a handful of brilliant artists who ignited the Renaissance. Teeming with rich patrons, like the Medici and the Strozzi, and with thousands of churches and chapels needing walls covered and altarpieces filled, the capital of Tuscany was the furnace in which modern art was forged. Without the unparalleled explosion of talent in Leonardo’s and Michelangelo’s time, the city’s fortunes would have been very different. Who knows what it would look like today.

It makes sense, then, that Florence is twinned with Edinburgh, a pairing that dates back to 1964. One created the Renaissance, the other lit the fuse beneath the Enlightenment, which was to rip through Europe, setting it alight. Florence showcased Brunelleschi, Giotto and Ghiberti, while its northern partner nurtured David Hume and Adam Smith. One appealed to the senses, the other to the intellect. Both are founded on banking and finance, their hearts beating in time with the stock market. Each is obsessed with status, class, and appearances. The upper echelons can be chilly and aloof, and in their grand villas and offices it is old money that talks loudest. The nouveau riche will gain entry, but never acceptance. Nor is it coincidence that, floating on so much wealth, both are exquisitely beautiful.

Many years ago, when Labour was in power at Holyrood, there was talk of enhancing the twin-city link, and to this end a formal partnership that encompassed all of Tuscany and Scotland was proposed. I recall my selfless husband stopping the First Minister in the street and offering to become ambassador to Tuscany, even if it meant being posted to Florence. He said he’d do it for free, yet strangely, nothing came of it.

We’re in far more serious times now, of course. With the bond that connects us to Europe soon to be cut, is this not the moment to deepen the relationship with our Tuscan twin? If we could build on our friendship, and on our many mutual interests, we would counter at least some of the damage caused by being set adrift from the EU. Economic blight is bad enough, but to be severed from a region whose culture and people have immeasurably shaped ours is more insidiously harmful. What an oasis of civilisation and culture Florence and the rest of Tuscany would offer to those of us feeling left out in the cold. In turn, we could offer a bridge into Britain, showing that we have not turned our back on our continental European heritage, but are eager to keep it close.

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To do so would offer tangible results, for both sides. There are many forms it could take, from cultural exchanges, intellectual liaisons and trading or commercial enterprises to environmental partnerships – Florence was at the forefront of banning cars in the city centre – or historical and artistic projects. The benefits would ripple out. Perhaps as importantly as any pragmatic outcome, however, working more closely with our twin city and twin region would be a statement of intent. We refuse to be banished by Brexit to the back of beyond.