It is a bright spring morning and a couple of employees of the Sainsbury’s Local store in the commuter town of Oxted are giving a final wipe to the now pristine shop windows as a diminutive Dido Harding stands by the doorway, her arms folded as she inspects her store.

The former Tesco executive, who joined J Sainsbury as head of convenience just under a year ago, says she ordered the windows to be polished because she wants the store to look perfect.