In a letter to the bank, former National Assembly president Julio Borges and opposition party leader Carlos Vecchio said Maduro's socialist administration would pocket the last 14 tons of the Venezuelan gold in the bank's vaults or use it to illegally imprison and kill its opponents.
It reminded the bank that the United States, United Kingdom and many European countries consider Maduro's government illegitimate following his re-election this year in what was widely considered a fraudulent vote.
"Maduro is not the legitimate owner of the gold," the letter said. "Without doubt the intention of Maduro and his regime is to steal these resources that rightly belong to the people." Borges and Vecchio both live in self-imposed exile, saying they fear for their safety in Venezuela.
The Bank of England and Venezuela's communications ministry didn't immediately respond to requests for comment by The Associated Press. As the economic crisis mounts in cash-strapped Venezuela, Maduro increasingly relies on gold to make up for plummeting crude oil production. The once-wealthy oil nation is beset by scarce food supplies that have driven masses to flee Venezuela seeking a better life.
The Trump administration recently ratcheted up sanctions against Venezuela, targeting the country's gold sector by prohibiting U.S. citizens and entities from financial involvement in the trade. That was the latest round of U.S. sanctions already targeting Maduro and dozens in his administration as well as blocking Venezuela from access to U.S. financial markets.
In 2017, Borges was instrumental in rallying Wall Street against buying Venezuelan debt. He sent more than a dozen letters to international investors saying they risked their reputations by throwing a lifeline to Maduro.
The letter to the Bank of England says that allowing Maduro to repatriate the gold would further breach the bank's legal obligation to prevent money laundering and corruption spelled out by law.