The men, working for C and D Industrial Services, held an unofficial strike this week but were told on Friday they had lost their jobs.

The contract workers had claimed their pay was less than that of workers in similar positions at the yard despite some having been there for up to 20 years.

Since 1990, the contract workers claim their pay has only increased by �3.30 an hour.

Unions said they urged their members to go along with the legal process of holding talks with managers at C and D Industrial Services, but said the men became frustrated and staged an unofficial walkout.

We are supporting them on the claim, but we cannot condone the walkout David Harrison, Amicus

The unions said they hoped to be able to carry on discussions with the workers and the company to resolve the situation.

Dave Harrison, from Amicus said they supported the 98 workers but did not support the walkout.

He said: "They are all time-served craftsmen and they are receiving �1.95 an hour less than the time served craftsmen who work directly for the yard.

"They are saying they should be on the same hourly wage as the lads in the yard and the union supports them on that.

"They were advised and they knew there was a possibility they could be dismissed if they staged an unofficial walkout.

"We are supporting them on the claim, but we cannot condone the walkout.

"They have to get back into the formal legal requirements that are set in place for us to progress in negotiations."