The Observer said that the c-store and petrol forecourt sector will account for almost £1 in every £3 spent on groceries within five years.

Research published by analyst at Verdict said that these outlets will grow grocery sales faster than superstores for the first time in decades.

Verdict said Tesco's move into the c-store sector has put pressure on existing players and prompted rivals such as Sainsbury to develop their own formats and to make acquisitions.