This week's launch of Walkers Extra Crunchy has caused a spat among independents claiming to be first to stock the product.

Although Walkers has insisted that the new range was not given exclusively to anyone, enterprising ­retailers opened at midnight last Sunday to sell the product first.

In a move more akin to a book or computer game launch, a Spar store in Bentley opened its doors at 11:59pm, enticing customers with a giveaway, with prizes including digital cameras and crisps.

"Our stores love being involved in launch events like these. It helps strengthen brand awareness and gives stores a great buzz up to launch time," said Nadine Sandle, trainee buyer at Spar wholesaler AF Blakemore.

Meanwhile, a Londis store in north London was also claiming to be the first to stock the product. The store, in Hendon, was used to film the Walkers TV ad featuring Gary Lineker and Lionel Richie, which will air from 27 August. Londis and Budgens owner Musgrave Retail Partners GB claims the launch, the biggest by Walkers in 10 years and supported by a £3.5m marketing campaign, will generate £1.2m in sales for both fascias.

Walkers said it was supporting indies by creating 99p price-marked variants of Walkers Extra Crunchy.