Leicestershire Police found almost half a million pounds in cash after they stopped a vehicle in a Leicester street.
Officers had flagged down the van in a stop-check search when the cash was discovered.
The van was stopped on Roundhay Road, in Rowley Fields, on Tuesday evening. When officers searched the van, they found £465k in cash in the van.
The driver has been arrested and remains in police custody. Leicestershire Police said the man will be transferred to West Midlands Police, as the arrest relates to an ongoing investigation.