Waitrose has avoided a formal investigation by the Advertising Standards Authority (ASA) after it agreed not to repeat adverts saying “everyone who works at Waitrose owns Waitrose”.

The supermarket chain is part of Britain’s largest employee-owned retailer, the John Lewis Partnership, which is under pressure to renegotiate its deal with cleaning contractors and be more honest about how it treats workers who are not members of its employee benefit trust. Over 142,000 people have signed a petition demanding it pay its contracted-out cleaners the living wage.

Justine Grimley, senior investigations executive at the ASA, said it had received 268 complaints about the ad. The ASA then spoke to Waitrose, which said it had based the claim on its partnership scheme, she added.

“They had intended to convey a message about the values of members of the scheme, rather than comment on the wider practices of Waitrose or other employees, who were perhaps working for Waitrose on a contractual basis,” she said.

“Regardless, they acknowledged that the claim had caused a high number of complaints to the ASA, which in itself was a serious issue, and assured us that they had no wish to mislead Waitrose customers or the wider public with their marketing material. To try to address consumer concerns, they gave an assurance that the ad would not be repeated and that all locations where the claim continued to appear would be identified so that the ads there could be withdrawn or amended.

“Given Waitrose’s prompt response to the complaints and the steps they have proposed, we have agreed to resolve the matter on an informal basis this time.”

According to campaigners, a statement in Waitrose stores says “everyone who works for Waitrose owns Waitrose”. Activist Jane Lambert said: “It’s a subtle change of language which again might mislead customers who aren’t aware that any cleaners they see are outsourced and that other groups of staff – for example, temporary staff – might also be excluded from full partnership benefits.”

She added that protests had revealed that many customers were unaware that John Lewis Partnership cleaners did not receive a living wage and that campaigners were planning a year of action to change that.

A spokesperson for Waitrose said: “We were made aware of the complaints and as a result have reassured the ASA that the campaign line will not be running again in its exact form.”

She added that the other wording was not related to the ASA issue, which only applied to television advertising.