Also known as the tea treat or revel bun, the saffron bun is the Cornish answer to the tea cake. A rich yeasty mix containing currants the key ingredient is, yes you guessed, saffron!
Being relatively exotic and made from the stamens of thousands of crocus flowers, saffron doesn't come cheap. In fact there is a local expression, "as dear as saffron".
It therefore seems a little strange that saffron should find its way into a traditional Cornish bun. One suggestion is the spice may have been imported as far back as the times the Phoenicians traded tin with the Cornish.