The British central bank said it would allow high street banks to swap mortgage-backed securities for government bonds in a bid to boost their liquidity.
"The Bank of England is today launching a scheme to allow banks to swap temporarily their high quality mortgage-backed and other securities for UK Treasury Bills," it said in a statement.
It added: "Discussions with banks suggest that use of the scheme is initially likely to be around 50 billion pounds (63 billion euros, 99 billion dollars)."
Britain's main home loan providers are tightening their lending criteria amid mounting fears over the sector's exposure to the collapsed US subprime housing market and a subsequent global squeeze on credit.
In recent months, a growing number of high street banks have increased the interest rates they charge to their customers for home loans, contributing to a sharp slowdown in British house prices.
The BoE added Monday that it would allow banks to swap their mortgage-backed securities over