Shares in the AA have taken a dive after the executive chairman of the roadside recovery and insurance business, Bob Mackenzie, was sacked for gross misconduct.

The markets were told yesterday (Tuesday, August 1) that Mackenzie had been removed from all roles at the company with immediate effect. 

Shares in the business dropped 18% when the news broke, but closed the day down 14% at 210p. The 33p fall in the share price left it below the 250p price at which it floated in June 2014. However, it had recovered slightly to 214p the following day.

Mackenzie had led the AA since overseeing a management buy-in of the company in June 2014, which led to its shares being listed on the stock market. Before that, the company had been owned by private equity firms Permira, Charterhouse and CVC.

The AA said he would be replaced by non-executive chairman John Leach, who joined the AA in June 2014 as a non-executive director and was appointed as senior independent director five months later. He is also chair of the nomination committee and a member of the risk and audit committees.

Simon Breakwell has been appointed as acting chief executive. He joined the AA in September 2014 as a non-executive director and is currently chair of the remuneration committee and a member of the nomination committee.

Outside of the AA, he is a Venture Partner at TCV, one of the leading global mid cap funds, and chairman of Business Data 4 Travel.

Breakwell was a founder of Expedia and a member of the main board for 10 years from 1996. More recently, he was responsible for establishing the European operations for Uber.com.

In a statement, the AA gave no further details about Mackenzie's departure, but said: “As detailed in the annual report, the board had already begun the process of splitting the combined roles of executive chairman as the company nears the end of the transformation programme. The nomination committee will now accelerate this appointment of a chief executive.”

Andrew Blowers has been appointed as senior independent director, replacing Leach in that role. He joined the AA in September 2014 as a non-executive director and is chair of the risk committee and a member of the audit and nomination committees.

Martin Clarke continues as the chief financial officer.