The airline has said it will be able to fly 5 per cent more passengers during the first planned strike because of the growing number of cabin crew calling in and offering to work.

International support for the planned industrial action by the BA cabin crew has spread, with unions representing ground staff in the US, France and Germany pledging their solidarity with the strike.

The European Transport Workers' Federation said it was backing the BA strike, while the Brotherhood of Teamsters in the US said it is looking at ways it can help the striking BA workers. Germany's ver.di service workers union also said it was ready to help Unite in its move.

BA chief executive Willie Walsh said more cabin crew have offered to work because of their "disillusion" with Unite, the union organizing the strike. The airline "will now have the potential to fly more than 4,000 additional customers per day and serve more destinations," he added.

BA has claimed that up to a thousand staff have volunteered to work, and it expects the number to rise. But Unite accused the management of bluffing and said only 350 employees were prepared to stand in for the strikers. A three-day strike by Air France cabin crew over working conditions has been planned for 28 March to coincide with Unite's industrial action.