A woman arrested on suspicion of an offence under the Official Secrets Act has been released pending further investigation.
The 65-year-old, who is contracted to carry out work for a government department, was held in north London on Wednesday.
She was arrested by officers from Scotland Yard’s counter-terrorism command on suspicion of an offence contrary to Section 1 of the Official Secrets Act 1911.
The Metropolitan Police said on Thursday: “She was subsequently released under investigation.
“Officers have also completed a search at an address in north London as part of the investigation.