A Ministry of Defence official will appear in court on Thursday charged with breaching the Official Secrets Act, Scotland Yard has revealed.
Edward Devenney, 29, is accused of communicating information on January 28 this year which could be deemed to be useful to an enemy of the state.
He was arrested by officers in Plymouth on Tuesday morning before being charged on Wednesday night, the Met said.
A Metropolitan Police spokesman said a number of searches had been carried out in connection with the arrest which were now complete.
Devenney, of Northern Ireland, will appear in custody at Westminster Magistrates' Court on Thursday.