LONDON, April 9 Reuters Bank of England bond buying may actually increase the speed with which future interest rate rises make UK government debt unbearable and is one glimpse into why central banks need to tread lightly around postpandemic debt piles for many years.

Britain publicly prides itself on keeping the average maturity of its national debt much longer than other major economic powers sensibly reducing the threat of refinancing crunches, rollover risks and cutting shortterm interest rate sensitivity into the bargain.

The UK Treasurys Debt Management Office claims the average maturity of its total stock of debt was a whopping 14 years at the end of last year well over twice the U.S. equivalent and six years longer than the next closest G7 partner France.

But after warning about the interest rate sensitivity of UK government debt for the past year, the Office for Budget Responsibility OBR the governments own budget watchdog last month detailed just why the seemingly comfortable G7 comparison disguised a counterintuitive effect of the BoEs bond buying.

The Bank of Englands BoE onoff government bond buying programmes since the financial crash 12 years ago, at least partly designed to keep longterm borrowing rates low, basically involve the purchase of gilts from banks in return for interestbearing reserves at the central bank rather than cash per se.

And the interest rate on those bank reserves currently a record low 0.1 is the very Bank Rate the BoE uses…