The Prime Minister has called them to Downing Street for breakfast talks on Tuesday before he departs for a visit to the US, where the global financial turmoil will be high on the agenda.

And the country's biggest lenders will later face a crunch summit with Chancellor Alistair Darling in a bid to find ways to help ease the situation.

The Bank of England cut the base rate last week for the third time since December, but experts have predicted the cost of borrowing will continue to rise.

Writing in the News of the World, the Prime Minister said Mr Darling would discuss "new measures to ensure those lower interest rates are passed on to mortgage holders". And he called on the biggest financial institutions to work together to ensure potential future problems were not kept secret.

"Although the Bank of England has cut rates in recent months, the banks have not always been passing those reductions to their customers," he wrote.

"So Alistair Darling will be meeting with the main mortgage lenders to discuss what further steps can be taken."

He went on: "To create the conditions where banks feed through their interest rate cuts to homeowners and new buyers, we must first rebuild confidence in the banking system and reduce the uncertainty that is currently holding the banks back from lending to each other..

"If the world's largest banks could come together quickly and agree as a group to come clean about the potential bad debts they face, we could reduce the uncertainty and risk they face and restore confidence back into the markets."

An extra £15 billion was also being injected into the market by the Bank of England, he noted. "We need to do more to see this feed through to improved availability of mortgage lending."