An app is launching in October that aims to “transform” local shopping and boost the fortunes of independent retailers by sending real-time deal alerts to consumers.

The Big DL app is backed to the tune of £17m by leading investor and entrepreneur Brian Duffy and owned by Internet Access Technologies, a company founded by tech start-up expert Matt Norbury, who has a “history of innovative products and technologies price comparison, loyalty, customer satisfaction and mobile marketing,” according to a spokesman.

The service works by adding an in-store “beacon” to stores, which connects with the app to trigger exclusive deal alerts when the device is within a 20-mile radius of the shop.

“It’s innovative, new and unique,” added the spokesman. “An alcohol brand could do a proximity-based promo in Londis, so when a consumer walks past they could receive a notification offering them 20% off that particular brand. They can then wander into the Londis, swipe their phone and get that discount. It’s a unique proposition.”

Whisky brand Whyte & Mackay has already signed up to Big DL, as well as Londis and Heron Foods. The service costs £7.50 per week, per store, and Big DL is guaranteeing ROI, by vowing that if ROI isn’t delivered within three months it will continue to run the service for free until it is.

“They are looking to make it accessible for retailers, and because it’s new to the market they want to ensure that people are satisfied with it,” said the spokesman. “This guarantee is their initial promise coming out of the gate. It ensures that they receive back what they invest in the proposition by way of trackable measureable results.”

Big DL also plans to allocate £5m in year one to promotion, including advertising on national TV.