Almost 95% of the union members - who produce planes including the 737 Max and 777 - voted in the ballot rejected the pay deal.

Of those who voted, 96% back strike action until a new agreement is reached.

As well as a 25% pay rise over four years, the preliminary agreement that workers rejected included a commitment from Boeing to build its next commercial plane in the Seattle area if the project started during the lifetime of the contract.

The union had initially targeted a number of improvements to workers’ packages, including a 40% pay rise.

On the face of it, it is hard to see a quick solution unless Boeing capitulates.