The AA, which listed in London in 2014, has a stock market value of 914 million pounds. It refinanced its debt earlier this year, extending the average maturity as well as cutting annual interest cots.

The cost of its annual debt interest has been reduced by 90 million pounds since its listing.

"GMB members working for the AA are seriously worried about the scale of debts and the cost of financing them and how this is impacting on their day to day lives," GMB Regional Organiser Paul Grafton said on Friday.

The AA said this week it was selling its home emergency services policy book to Homeserve for an undisclosed sum.

GMB said its members were concerned that the debt pile could lead to further divestments.

The company appointed Simon Breakwell as acting chief executive in September following the sudden dismissal in August of Bob Mackenzie for gross misconduct.

The GMB is not the recognised union for AA employees, an AA spokeswoman said in an emailed statement. Another union, the IDU, is the AA's recognised union, she added.

(Reporting by Carolyn Cohn; editing by Jason Neely and Elaine Hardcastle)

Stocks treated in this article : AA, Homeserve plc