LONDON (Reuters) - British counter-terorism police said they had arrested a woman on Wednesday under the Official Secrets Act.
The 65-year-old woman was contracted to carry out work for a government department, they added, without elaborating.
She was being held at a south London police station while officers searched an address in north London.
No further details were immediately available.
Reporting by Stephen Addison; editing by Guy Faulconbridge