The UK Supreme Court has begun a three-day hearing to determine the legality of hidden commission payments made by lenders to car dealers, a case that could result in billions of pounds in compensation for consumers. The appeal, launched by banks including FirstRand Bank and Close Brothers, challenges a Court of Appeal ruling from October that deemed such payments unlawful. The Financial Conduct Authority (FCA) has intervened in the case, arguing that the previous ruling by the Court of Appeal 'goes too far' in treating motor dealer brokers as owing fiduciary duties to consumers. The FCA's stance could limit the scope of potential compensation claims, as it suggests that motor dealer brokers do not typically owe such duties. The case has significant implications for the financial industry, with major banks like Lloyds Banking Group, Close Brothers, and Santander UK having already set aside over 1.5 billion pounds to cover potential claims. Analysts estimate that the total industry cost could reach 30 billion pounds if the Supreme Court upholds the previous ruling.