Not getting consent from an ethics committee

We had provisionally accepted a randomised controlled trial of an exclusion diet given to young children with a particular condition. The trial design was that one group started the exclusion diet a month before the second group. In other words, both were given the “treatment.” One part of the trial was that children who were thought to have an allergy to a particular food were rechallenged with that food. We discovered rather late in the day that the study had been done without ethics committee approval, despite the fact that the trial had been carried out in a major British hospital. The reason the authors gave for not submitting the study for ethics committee approval was: “because all children received advice on dietary exclusion. The only difference between the control and the trial group was that the dietary advice was delayed for a month. Thus all the children were given a trial of an exclusion diet as part of routine management. No drugs were involved. In view of this, ethics committee approval did not seem necessary. I discussed this informally with a member of the ethics committee who felt that this was a reasonable decision.” We rejected the paper on the grounds that ethics committee approval had not been sought, but should have been. But should we do more? Is this an example of research misconduct?