Its huge market share lays bare the long-term challenges faced by internet rivals Asda, Sainsbury's, Waitrose and Ocado, the online specialist that has never made a pre-tax profit in 10 years. Clive Black, an analyst at Shore Capital, has concerns over Ocado's ability to compete with Waitrose in the long term. "We believe that Ocado is largely Waitrose on wheels," he added.