Law firm CMS Cameron McKenna has doubted the effectiveness of the Office of Fair Trading’s investigation into supermarket practices.

The firm said that a number of its clients wanted to complain about supermarket practices but had not for fear that they would lose out on business.

When asked by the firm what they would say if they could complain anonymously, the complaints focused on the conditions retailers place on suppliers and buying practices.

Louise Wallace, head of consumer products at CMS Cameron McKenna said: “It is telling that only when we assured our respondents of anonymity they felt able to voice serious concerns about the relationship between retailers and manufacturers.”