The Bank of England said today that it would buy as many long-dated government bonds as needed between now and October 14 to stabilise financial markets, and added that it would postpone next week's start of its gilt sale programme.
"Were dysfunction in this market to continue or worsen, there would be a material risk to UK financial stability," the Bank of England said.
"This would lead to an unwarranted tightening of financing conditions and a reduction of the flow of credit to the real economy," it added.
The bank said the purchases were designed to restore orderly market conditions.
"The purchases will be carried out on whatever scale is necessary to effect this outcome," it stated.
Earlier 30-year British government bond yields rose above 5% for the first time since 2002, as a sharp sell-off triggered by last week's government fiscal statement continued.
Following the Bank of England statement 30-year yields dropped around 20 basis points on the day.
The Bank of England said it was keeping its goal to reduce its £838 billion of gilt holdings by £80 billion over the next year, but would postpone the start of sales - due to begin next week - because of the market conditions.
The Bank of England said it would sell back the gilts it buys once market conditions had stabilised, and that Britain's finance ministry had agreed to indemnify it against any losses.
"These purchases will be strictly time limited. They are intended to tackle a specific problem in the long-dated government bond market," it added.