Britain’s car finance industry is in disarray and analysts suggest payouts could equal the country’s costliest consumer bank scandal. The move follows a landmark ruling in late October from the UK Court of Appeal, which ruled that it was illegal for car sellers to receive bonuses from banks that finance car purchases without explicit permission from customers.

The judgment bears some resemblance to the PPI mis-selling scandal, for which the value to the banks was put above £50 billion ($63.8 billion). Policymakers seem to have taken everybody by surprise, and the public was expecting a gigantic redress scheme that could compensate consumers.

Britain’s financial watchdog, the Financial Conduct Authority, said it will ask the Supreme Court to consider a speedy ruling on whether lenders can appeal the judgment. While motor finance companies might face a rise in complaints, the authority asked them to put aside provisions for compensation. The authority also said that it would aid if the Supreme Court would permit an appeal.

Uncertainty attached to the ruling has left banks in limbo, observers and analysts such as Niklas Kammer of Morningstar have pointed out. Lloyds Banking Group via its Black Horse brand is most vulnerable while Barclays risks associated with it, albeit to a much lesser extent. This decision raises questions about what regulatory framework banks should resort to, but the existing order is not reflective of the Court of Appeal’s decision.

Warning the market for losses of as much as £28bn if the Supreme Court upholds the ruling, U.K. banks analyst at RBC Capital Markets, Benjamin Toms, said this move may lead lenders to withdraw from the market, reduce consumer choice, and drive up prices for vehicles.

The crisis also underlines broader worries over lending practices. Rating agency Fitch has already put Close Brothers Group on “Negative Watch” owing to its exposure to motor finance. As developments come from within the industry, the full extent of the financial blow remains far from clear.