John Palmer, dubbed "Goldfinger", who built up a fortune after his acquittal in the trial which followed the infamous robbery in 1983, is believed to have walked into a central London police station after being contacted by police investigating an alleged international timeshare fraud.
Yesterday, Scotland Yard said only that "a 47-year-old man attended Holborn police station this afternoon after police had arranged to meet him there. He has been arrested, in connection with allegations of fraud by the Metropolitan Police Organised Crimes Squad."
A woman also arrested yesterday in connection with the same inquiry was thought to be Mr Palmer's 36-year-old girlfriend, Christine Ketley.
Last month, officers from the organised crime squad were investigating allegations of fraud in connection with two companies, Timeshare Resales USA and Springbok International.
It was reported that the inquiry centred on deals in Tenerife, where Mr Palmer moved after being acquitted of the Brink's-Mat charge.
Along with his wife Marnie and their two young children, Mr Palmer had gone there by chance on a package holiday in 1985 when police raided the family home near Bath in a search for signs of stolen gold.
None was found, but a huge smelter was taken away for examination. Mr Palmer's holiday was extended indefinitely, and he spent his time setting up timeshare operations.
He later went to Rio de Janeiro, but was forced to leave immediately on a plane to London where detectives were waiting.
At the trial, two robbers in the pounds 26m Brink's-Mat gold bullion haul were sentenced to 25 years, and a former Brink's-Mat employee got six years. Three other men have been convicted and jailed for handling the bullion.
When Mr Palmer was acquitted of smelting the Brink's-Mat gold, he blew a kiss to the jury as he left the court and then returned to Tenerife.