Another week, another BBC Four  history/travel series. The Silk Road (1 May) had all the raw ingredients of the genre – beautiful photography, quaint locals, a presentable presenter – without­­ turning them into anything nutritious.

In place of new ideas, it had a presentational gimmick: a hefty blank notebook carried by presenter Dr Sam Willis. As he travelled, Willis added photographs, drawings and handwritten notes. The latter were particu­larly beautiful, suggesting the possibility that he was chosen for his penmanship as much as his youthful air and neat, unhipsterish beard.