Of concern to Tesco is the 80 per cent of shoppers who said the retailer had already crossed that line and was a threat to small shops.
Seventy-seven per cent said they sensed the beginning of a backlash against the dominance of the big-name supermarkets.
Opinion Matters polled 1,562 shoppers from 29 April-1 May for the survey.
More than 40 per cent named Tesco as their supermarket of choice – only slightly less than the combined figure for Asda, Sainsbury's and Morrisons.
The results could confirm that the campaigns of various organisations, such as Friends of the Earth, against high-street homogenisation and big-chain dominance have affected attitudes.
But Tesco's announcement last week of record annual profits suggests such campaigns have yet to affect its commercial performance.
Tesco external comms manager Jonathan Church said the group's strategy had always been 'to do the right thing by shoppers in stores'.
He added: 'However, this survey shows consumers do base their shopping decisions on a broad base of factors, and not just price and food quality. Ethics, local shops and food miles are of concern for consumers, and they can see we're doing our best to address these.'
Tesco has turned its £2.2bn profit announcement into something of a PR triumph. In the Tickbox poll, 63 per cent labelled the firm a British success story.
With the Competition Commission on the brink of announcing a two-year investigation of the grocery sector, the big chains are
already attempting to soften their image.
For example, Sainsbury's this week hired ex-BBC News anchor Anna Ford as a non-executive board director, to focus on 'anything of public interest'. A Sainsbury's spokeswoman said most of the board had a background in finance, and Ford would give it 'a broader view of public concerns'.