It was a factory renowned for making boiled sweets, toffees and chocolate. But in 1949, Needler's in Hull was the location for an episode of a BBC radio programme that was broadcast to the nation.

In a factory in a residential area of Dudley, one family's top secret recipe for hard boiled sweets has been bubbling and boiling away in copper pots for the past 200 years. "It is not a fad, it is ...