THE PRIME Minister today criticised the walkouts at Southampton and other places around the country sparked by a bitter dispute over foreign labour.

Gordon Brown condemned wildcat action such as the 140 workers who downed tools at Marchwood Power Station as "indefensible."

He claimed his promise of British jobs for British workers only meant he planned to give more training to the domestic workforce so it could compete with other nationalities in the single European market.

In an interview to be broadcast tonight on the BBC's Politics Show he said of the walkouts: ''That's not the right thing to do and it's not defensible.

''What we've set up as a process to deal with the questions that people have been asking about what has happened in this particular instance.

''When I talked about British jobs, I was taking about giving people in Britain the skills, so that they have the ability to get jobs which were at present going to people from abroad and actually encouraging people to take up the courses and the education and learning that is necessary for British workers to be far more skilled for the future.''

Marchwood workers claimed anger over the number of foreign workers being taken on has been mounting in the industry for years and in the current climate has boiled over.

A spokesman for Siemens, who are in charge of the construction at the Marchwood site, said: "We are aware that some workers on the Marchwood site have walked out and we will be assessing this situation over the coming days."

When the £350m power station is completed later this year it will generate enough electricity to supply Southampton, Winchester and the New Forest.

Marchwood Power directly employs about 50 people but currently almost 800 construction workers are employed on the site through Siemens.

The series of strikes broke out after energy giant Total's decision to bring in hundreds of Italian and Portuguese contractors to work on a new £200 million plant at the giant Lindsey Oil Refinery at North Killingholme, North Lincolnshire.

Union bosses claim Britons were not given any opportunity to apply for the posts.

Paul Kenny, general secretary of the GMB union, said: ''No company should be able to discriminate against anyone on the grounds of where they were born.

''You simply cannot say that only Italians can apply for jobs as has happened in this case.

''No-one is saying that different countries cannot bid for different contracts.

''What is happening here would be illegal under UK domestic law.''

Mediator Acas was drafted in on Friday night by employment minister Pat McFadden to attempt to resolve the situation between the opposing parties, amid threats of mass industrial action.

Union leaders and representatives of engineering construction firms and contractors are expected to meet in London next week in a bid to find a way of resolving the row.

The so-called National Joint Council will meet on Wednesday.

This will be followed by a meeting of union shop stewards a few days later.

Mr McFadden said he had asked Acas to examine claims that British workers were being illegally excluded from some major engineering and construction projects.

There was speculation that the dispute will escalate tomorrow and spread ''like wildfire'' across the country if the deadlock is not broken.