In holiday brochures, Zanzibar is an “exotic and mysterious” archipelago where, in the tight, mazy streets of its capital Stone Town, intrepid honeymooners and others are promised they will discover its “secrets”.

But while about 140,000 travellers pause each year to admire the intricately-carved wooden doors that are an imposing mark of the islands’ Arab heritage, the reality is that, to most visitors, they remain firmly shut.