The Royal Bank of Scotland (RBS) has announced more losses in the first three months of 2009 and warned of an "uphill battle to fight off bad debt".

The part-nationalised bank, of which taxpayers own more than 70 per cent announced bottom-line losses of £857 million and bad debt charges of £2.9 billion.

RBS said a lame three months for its investment banking division had been offset by the impact of record low interest rates on margins and steadily rising bad debts due to the financial downturn.

The bank witnessed impairment charges on its loans rise to 1.33 per cent in the first quarter, it also booked an additional £2.1 billion on credit card exposures.

The bake is insuring more than £300 billion of toxic debts in a taxpayer-backed insurance plan but is liable for the first £19.5 billion of any loss.

Chief executive Stephen Hester held a bleak outlook over a speedy recovery for the business, saying that this year and next would be “very tough” for the group. He added: "No-one should be in any doubt that this is a process that will take years not months."