Markets fear the plan will drive up inflation, forcing the Bank of England to push interest rates as high as 6% next spring, from 2.25% at present.
“Were dysfunction in this market to continue or worsen, there would be a material risk to UK financial stability.
To prevent that happening, the central bank said it would buy long-dated UK government bonds until October 14.
Yields on 10-year UK government bonds fell sharply after the Bank of England’s announcement on Wednesday but remain elevated.
UK interest rates have risen seven times since December 2021.