LONDON — Share prices went through the roof, speculation ran wild and money poured into ill-fated ventures before the boom turned, inevitably and catastrophically, to bust.

After that financial crash in 1720, called the South Sea Bubble, the British government was forced to undertake a bailout that eventually left several million pounds of debt on its books. Almost three centuries later, Britons are still paying interest on a small part of that obligation.

Now, prompted by record low interest rates, the British government is planning to pay off some of the debts it racked up over hundreds of years, dating as far back as the South Sea Bubble.

George Osborne, the chancellor of the Exchequer, said this month that in 2015 Britain would repay part of the country’s debt from World War I, and that he wanted to pay off other bonds for debt incurred in the 18th and 19th centuries.