Leyla Kazim visits York, the UK's 'chocolate city', on the centenary of Joseph Rowntree’s death, to find out how the Quaker entrepreneur pioneered both social reform and iconic chocolate brands like Smarties and Kit Kat.

Today, many independent chocolate makers still call York home, as do some of the word's biggest multinational confectionary makers. Leyla Kazim wanders through York Chocolate Festival to trace the city’s unique chocolate heritage and find out what changed when global companies got involved.

As the so-called 'Dubai chocolate' drives a frenzy of demand for filled bars and imitations, Leyla meets a Newcastle chocolate maker with a penchant for wacky flavours and who inspired the original sell-out hit.

Leyla also hears how falling global production and high prices of cocoa could be the end of chocolate as we know it.

Produced by Nina Pullman for BBC Audio in Bristol.