By Jonathan Davies

Clydesdale Bank has been fined £20.7 million for "serious failings" over Payment Protection Insurance (PPI) claims.

It is the single largest fine handed out by the Financial Conduct Authority (FCA), the City regulator.

The FCA said that as many as 93,000 Clydesdale Bank customers may have been entitled to refunds or compensation.

The bank changed its policy in May 2011 which resulted in complaint handlers not taking into account all relevant documents when assessing PPI claims. The bank apologised and said it has now changed the policy.

It also provided provided false information to the Financial Ombudsman in 2012 and 2013. And some PPI files were even deleted from customer records.

Together with its sister company Yorkshire Bank, Clydesdale Bank has set aside £806m for PPI fines and compensation.

"As soon as this issue was discovered, we took immediate steps to stop it; we made the regulator aware and rapidly introduced strict new monitoring procedures to prevent any recurrence," said acting chief executive Debbie Crosbie.