The Royal Bank of Scotland (RBS) has posted a loss of £1.4bn for the six months of 2011, compared to a profit of £9m for the first six months of 2010.
The bank said its exposure to the Greek debt crisis and costs relating to the mis-selling of Payment Protection Insurance (PPI) pushed it into a loss.
RBS in the latest period it had set aside £733m towards covering exposure to Greek sovereign debt and made a provision of £850m to cover costs for mis-selling PPI.
After Societe Generale and BNP Paribas, RBS became the latest European bank to take a hit for holdings in Greek sovereign debt.
RBS, which is 84% owned by the taxpayer, posted operating profit of £1.87bn for the first half of 2011 against £1.13bn in the corresponding half of 2010.
RBS chief executive Stephen Hester said the results showed the bank’s restructuring continued and "business performance is resilient in challenging market conditions.
"There is no shortcut to achieving our goals. Economic and regulatory headwinds may be challenging but the momentum that our people and restructuring actions have sustained thus far in the RBS recovery plan should continue to stand us in good stead," he added.