If confirmed, it would be one of the biggest confiscations of criminal goods in history.
British police also seized seven million pounds in cash and securities, cocaine, ecstasy tablets and amphetamines, the prosecution service said on Thursday.
They also made 10 arrests after receiving information from Colombia's Technical Investigation Department, or CTI.
The British Embassy in Bogota made no immediate comment, and in London Scotland Yard said it was unaware of any such arrests or confiscation in the London area.
No one could be reached immediately at either the National Crime Squad, which oversees drugs raids across the country, or at Customs and Excise.
The sum confiscated was confirmed to reporters by the CTI's director, Guillermo Ortega, who referred to the "the figure, not to be sniffed at, of $6 billion."
Two suspects have also been arrested in Colombia and another two in Ecuador, Ortega said, providing no details of what type of securities had been seized.