Tourists who queue for hours outside the Uffizi to see Botticelli’s ‘Primavera’ and ‘Birth of Venus’ are sometimes surprised to find his world-famous paintings upstaged by the work of a non-Italian they’ve never heard of.

At three metres tall and five metres wide, Hugo van der Goes’s ‘Adoration of the Shepherds’ – known as the ‘Portinari Altarpiece’ – is certainly imposing, but it’s not the size that impresses so much as the colour: beside the glow of its Flemish oil paint, Botticelli’s tempera looks pasty.