A class - action case brought against Mastercard on behalf of 46 million customers has been revived after being dismissed by the Competition Appeal Tribunal in July 2017 on the basis of Mastercard 's arguments against calls for compensation . The case, brought by former financial services ombudsman Walter Merricks CBE, was brought on behalf of consumers alleged to be victims of excess ‘interchange fees’. The Court of Appeal in London has granted permission to appeal against the dismissal , brought on behalf of alleged victims of excessive " interchange fees " . The claim , for £ ##500 ( $ 18bn ) in damages , is the largest ever in English legal history . It follows the introduction of the Consumer Rights Act 2015 , which provides for " all - out " collective action on behalf of individuals .
A class - action case brought against Mastercard on behalf of 46 million customers has been revived after being dismissed by the Competition Appeal Tribunal in July 2017 on the basis of Mastercard 's arguments against calls for compensation . The Court of Appeal in London has granted permission to appeal against the dismissal , brought on behalf of alleged victims of excessive " interchange fees " . The claim , for £ ##500 ( $ 18bn ) in damages , is the largest ever in English legal history . It follows the introduction of the Consumer Rights Act 2015 , which provides for " all - out " collective action on behalf of individuals .