Crew who serve as part of British Airways' 'mixed fleet' - and have poorer terms and conditions than some longer-serving staff - rejected a pay offer from BA shortly before Christmas.

"Unite remains hopeful that a negotiated settlement which meets our members' aspirations can be achieved and would urge British Airways to engage constructively in meaningful talks to address poverty pay," the trade union said.

BA said that 'mixed fleet' Unite represented 15 percent of its cabin crew and that the airline was working on a contingency plan to ensure its customers reached their destinations.

It said in a statement that it would give more details on Jan. 6 once it had finalised the contingency plan.

(Reporting by Andy Bruce and additional reporting by Ismail Shakil in Bengaluru, writing by David Milliken; editing by Susan Thomas)