Video report by ITV News Consumer Editor Chris Choi

Shoppers at some of Britain’s biggest high street stores have been filmed by researchers to examine their buying behaviour, with some footage placed on a public YouTube channel, an investigation has found.

In a newspaper sting published today in The Daily Mail, an SBXL sales chief, Andy Bromley, was secretly filmed telling an undercover reporter: "These people don’t know they’re being filmed."

The Daily Mail reported Tesco, Boots and Co-op all commissioned SBXL, a behavioural analysis agency, to film customers in their aisles.

The firm has also worked with L’Oreal, Coca-Cola, Danone and Kellogg’s, the Mail said.

A screengrab of an SBXL employee telling an undercover reporter that consumers don't know they are being watched. Credit: Daily Mail

SBXL said adequate signage was in place and consent was sought from customers.

However, the Information Commissioner’s Office (ICO) said it was examining the Mail’s findings to check for breaches of data protection laws.

ICO director of investigations Steve Eckersley said: "The Daily Mail’s investigation has highlighted concerns about the use of CCTV. We will be examining the material provided and making appropriate inquiries."

YouTube videos on SBXL’s public channel showed footage of customers in stores, some of which had remained on the channel for eight years, according to the newspaper.

"The only people we film and study are those that give us express written consent before they go into the store." the managing director of SBXL, Phillip Adcock told ITV News.

He added: "We approach them outside of the store, we say 'this is what we're doing' would you like to participate?"

How have retailers responded?

Boots said it had been "let down" by SBXL and would not be working with the firm again.

The retailer said: "Clear signage and highly visible cameras were in place in the area of the store where the SBXL market research was happening and at no point were hidden cameras used.

"We’ve been let down by SBXL who have breached the terms of their contract with us by using our research clips in their promotional material and as a result we will not be working with them again."

Danone said: "We have not worked with this company for several years and have no current relationship with them."

Tesco told the Mail it "does not covertly film customers in stores nor would we allow any other company to do so" and that it worked with SBXL once in 2011 and customers gave permission to be interviewed.

A Co-op spokesman said: "We have only used SBXL for two limited trials, lastly in January 2018, and both times clear customer signage was in place, in line with the Market Research Society’s Code of Conduct rules and Data Protection legislation."

Kellogg’s said: "Kellogg’s UK used SBXL eight years ago (in 2011) for a single, six-week project in two individual stores.

"SBXL were members of the Market Research Society and therefore bound by their strict code of conduct. As part of that code of conduct, it stipulates that the footage would remain anonymous and only collected, held and shared responsibly with the consent of the shopper."

Coca-Cola said it worked with SBXL on a one-off project in 2015.