The banh mi is a staple street food in Vietnam and increasingly popular around the world. But how did it come to be a global sensation?

In this edition of The Food Chain, Ruth Alexander discovers how the signature sandwich - invented during the French occupation of Vietnam in the 1950s - went on to become popular around the world after the end of the Vietnam war.

Ruth explores the traces of French history and politics found in the sandwich ingredients with former French diplomat to Vietnam Dr Bertrand Hartingh; and she discovers how it’s made at Manchester restaurant, Pho Cue.

And as Dr Quan Tran of Yale University explains, it's a tale of ingenuity, adaptation and family love.

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(Picture: A banh mi sandwich)

Presenter: Ruth Alexander