The ballot, for industrial action short of a strike will involve the withdrawal of good will; for example, refusing to work overtime or extra hours. The ballot closes 10 February.

Prospect negotiator Helen Stevens said: “Members are angry that pay progression was stopped in 2011, leaving 73 per cent of employees earning less than the rate for the job.

“It is simply not right that most people are paid thousands of pounds less for doing the same job – and with the same stretching performance objectives – as their colleagues. For members already taking the brunt of the government’s austerity measures, this added unfairness hits right in the heart.

The UK HO is a successful organisation. Prospect members take pride in the specialist skills they deploy to ensure the safety of those at sea and to serve the national interest.

However, Prospect branch president John Bird said: “Enough is enough. The pay system is well and truly broken and a new and fair system must be put in place. We aim to forcefully convey the needs of the business as well as staff and demonstrate through our actions the impact of the lack of progress in fixing the problem.”