An email sent from Suella Braverman’s personal account on the day she had to resign over a security breach could throw fresh doubt over her claims about the speed with which she took action.
The email, seen by the BBC, told the recipient of a highly sensitive message that Ms Braverman had sent in error to “delete and ignore” it.
She has said she reported the mistake “rapidly” to officials.
But the BBC understands it took hours for her to respond.
Ms Braverman quit as home secretary 10 days ago because she had breached security rules relating to email use. She was then reappointed by new Prime Minister Rishi Sunak.