Borrow for a century, or even for ever, and there is less risk of Britain being hit by a refinancing crisis. The UK can use its current standing to secure cheap money for the next 100 years.
13 March 12 22:00 GMT
The government is considering issuing a new long-term bond it hopes will cut the country's interest payments for years, the BBC has learned.
At present, the UK government, like others, issues bonds - a form of IOU - which pay interest before being paid back after a fixed term.
A long-dated bond typically gives the government 30 years to repay in full.
The new plan is looking at issuing bonds with a 100-year repayment date, or even longer.
In his Budget next week, Chancellor George Osborne will announce that he will consult on creating a new "super-long" gilt that could even be issued with no set redemption date.
The theory is that these super long-term gilts would allow the government to lock in the current record low interest rate for a very long time.
If the bond proved popular with investors, future governments would pay less debt interest for years to come.
Treasury officials described this is like the country taking out a low rate fixed-term mortgage.
They said official figures reveal that the low cost of long-term interest rates will save the country £20bn in debt interest over the next five years.
The last perpetual loan was taken out to cover the cost of World War I.
The chancellor is accompanying Prime Minister David Cameron on his trip to the US where he will have meetings with his counterpart Timothy Geithner and head of the IMF Christine Lagarde.
Officials travelling with him say that next week's Budget has still not been finalised.
There will be another meeting of the coalition's governing "quad" on Friday.
The quad is the name given to meetings of the prime minister and chancellor from the Conservative side and the deputy prime minister and the chief secretary to the Treasury from the Liberal Democrat side.
One source said "things are still moving around" but insisted that many issues had been resolved.
The Treasury has to inform the independent Office for Budget Responsibility of its key tax and spending decisions by the end of Friday in order that the OBR can factor them in to its economic forecasts.
The Treasury is expected to spell out the details of its credit easing plan - to underwrite loans for small businesses - next Tuesday - on the eve of the Budget.
This post has been edited by inflating: 13 March 2012 - 10:14 PM