LONDON – Britain’s High Court ruled that a planned strike by British Airways cabin crews was unlawful, stopping the walkout just hours before it was due to begin.

BA said Monday that flights over the next few days will still be disrupted because it is too late to unwind contingency plans already put in place to cope with the planned 20-day walkout by members of the Unite union.

But BA said it aims to restore a full flying program at London’s Heathrow airport by the weekend, as long as the volcanic ash cloud that has shut airspace in recent days doesn’t cause further problems.

The High Court granted the last-minute injunction because of irregularities in Unite’s ballot of workers for the action. Unite, which represents around 90 percent of BA’s 12,000 cabin crew, had no immediate comment.