On 13 May 2021, the CAT ruled that DAF could not amend its pleas by adding general mitigation defences at the current stage of the proceedings against Royal Mail Group Limited (Royal Mail) and BT Group Limited & Others (BT). The case is expected to come to trial in April 2022. DAF sought to amend its pleas by adding additional general mitigation defences in relation to the passing-on of damage, i.e. that Royal Mail and BT mitigated any loss by negotiating lower input costs and/or otherwise reducing its costs of supply. The test for allowing such an amendment at a rather late stage in the proceedings is whether there is a realistic prospect of the plea succeeding at trial. The CAT ruled that for a defendant to be permitted to raise a plea of mitigation in such general terms as proposed by DAF, “there must be something more than broad economic or business theory to support a reasonable inference that the claimant would in the particular case have sought to mitigate its loss and that the steps taken by it were triggered by, or at least casually connected to, the overcharge (..)”. The CAT further held that where a defendant is in the position to make specific averments as to the alleged overcharge, it will be bound to plead them, rather than plead a wholly general allegation of mitigation of loss. The CAT added that in such circumstances, a general plea is liable to be struck out, or permission to amend refused. DAF had not pleaded such specific averments. Even though DAF could not could not be expected to know the detail of the internal operations of Royal Mail and BT, it could at least be expected to be aware of its own commercial dealings with each of them, according to the CAT. As there was therefore no factual support identified by DAF, the CAT was not persuaded that DAF currently had a sufficiently arguable case. Consequently, the application for permission to plead the general mitigation defence was dismissed.
 CAT 13 May 2021,  CAT 10, Case Nos. 1284-1290/5/7/18 (T).
 Para. 36.
 Para 37.
 Para 38.