In setting out the terms of its merger with Iberia, BA has left some responsibility for the deal in the hands of the one group arguably least-suited to it: the trustees of its pension scheme.

Under agreed terms, Iberia will be entitled to terminate the merger agreement if BA is required to put more funds into its pension scheme, which faces a yawning deficit. Severing the agreement could incur a €20m (£18m) break fee.