British Prime Minister Gordon Brown on Sunday condemned nationwide wildcat strikes over the use of foreign workers at a time of soaring unemployment, but unions warned more staff may down tools this week, according to Reuters. Industrial unrest is spreading across Europe, fuelled by a worsening economic downturn. Last week, French workers protested for more pay and job security while Greek farmers set up roadblocks, demanding compensation for low prices. In Britain, mounting tension between the ruling Labour Party and unions that provide much of its funds and support is also a taste of what may lie ahead for Brown's out-of-favour government as the recession bites, with an election due by May 2010. "That's not the right thing to do," Brown told BBC television when asked about last week's walkouts at energy plants across Britain. "It's not defensible." The government has asked an independent mediator to look at whether skilled British workers were unfairly debarred from contract work at a refinery in eastern England owned by France's Total. Thousands across Britain protested against the use of Portuguese and Italian workers at the site. "Whether you call it indefensible or not, a lot of people find it understandable in the circumstances," said Derek Simpson, joint chief of Britain's biggest union Unite. Unions have warned the strikes will continue and may even escalate as more workers across Britain discuss whether to join the action. Total issued a statement on Sunday evening saying it was operating in line with European Union rules and British law. "It has never been, and never will be, the policy of Total to discriminate against British companies or British workers," it said. It added that it would work with its sub-contractors to ensure British workers were considered for any vacancies. Business Secretary Peter Mandelson welcomed the statement and said he hoped it would help to head off further protests. "(It) should go a long way to meeting people's concerns, should reassure them and allow them to call off the unofficial action that we've seen in the last few days," he told BBC News 24. Brown's 2007 pledge to safeguard "British jobs for British workers" has come back to haunt him at time when he is urging the world to avoid a retrenchment into protectionism. Unemployment is rising sharply in Britain, up by 131,000 in the three months to November to 1.923 million. The rate of joblessness hit 6.1 percent -- the highest since 1999 -- and more big rises are expected as the downturn gathers pace. That is fuelling resentment against companies using European workers who, under EU law, are free to work across much of the continent and often accept lower pay than British staff. Mainstream politicians fear far-right groups such as the British National Party will turn the protests to their advantage. Opinion polls indicate Labour faces defeat by the Conservatives at the next election. Labour's recovery in opinion polls late last year had faded as the credit crisis hits families and businesses. The International Monetary Fund believes the British economy will shrink by 2.8 percent this year, making it the worst-hit of the Group of Seven leading industrialised nations and contradicting Brown's claims that Britain is well prepared for the downturn.