Britain could start selling 100-year and perpetual bonds, Treasury sources said on Tuesday, as ministers seek to lock in current low market interest rates to reduce the future costs of servicing the government's debt burden.
The Debt Management Office will launch a consultation alongside next week's budget to gauge the appetite for super-long bonds of 100 years up to gilts that never come to maturity, after initial discussions with investors proved positive.
The consultation with gilt market makers and funds will report back in three months, making the first tranche of any new bonds possible in the next financial year. Currently, Britain's longest bond matures after 50 years.
Issuing perpetual bonds, not seen in Britain since the end of the First World War - and before that, the aftermath of the South Sea Bubble in the 18th century - would mean the cost of servicing at least some of Britain's government debt portfolio would remain low even if future administrations had to pay higher interest on new bonds.
"This is about locking in for the future the tangible benefits of the government's credibility and the safe-haven status we have today," a Treasury source said. "The prize is lower debt interest repayments for taxpayers for decades to come."
Bonds with a maturity of more than 50 years are rare. Mexico and the Massachusetts Institute of Technology are among the few issuers of 100-year bonds.
Recent sales of long-dated UK gilts have met with strong demand, and yields on 50-year gilts hit a record low of around 3 percent in January.
With a perpetual bond, the issuer does not repay the principal sum, but can pay interest on it without a fixed end.