The son of former AA boss Bob Mackenzie said this evening that his father is "very unwell" and resigned his position at the firm due to ill health.
The statement comes after AA said it had fired Mackenzie for gross misconduct.
The company said it had removed Mackenzie, who was both chief executive and chairman, over a "personal conduct-related matter", sending its share price down by 14 per cent.
Speaking out this afternoon, Mackenzie's son, Peter Mackenzie, said his father was in hospital.
Peter Mackenzie told The Times: "This is an extremely distressing mental health issue.
"My father tendered his resignation this morning and resigned his directorship due to acute ill health, from which he has been suffering symptoms for some time. A consultant clinical psychologist advised him last week that he needed to take at least six month's leave.
"He is very unwell and has been admitted to hospital."
John Leach, a senior independent director at AA, has taken up the role of chairman, and Simon Breakwell has been made acting chief executive.
AA declined to comment.