Walkers is increasing the size of its grab bags by 20% in a move which it hopes will differentiate the bags from standard sizes, as well as create clarity over portion sizes.

PepsiCo head of impulse field sales Matt Goddard said: “Our research shows that when shoppers purchase our grab bags, it is for a completely different occasion than standard bags.”

According to Kantar data, one in five customers buys grab bags when shopping for savoury snacks.

Variants included in the bigger packs are: Walkers core range 60g; Doritos 66g; Quavers 41g; Monster Munch 48g; Wotsits 42g; and Squares 48g. All packs retail at 85p.