A rash of 1970s-style unofficial walkouts by British workers over issues such as tea breaks spurred employers to use foreign workers in the sector at the centre of a wave of industrial unrest in recent weeks, industry insiders have told the Financial Times.

More protests are planned next week over the use of foreign workers at Staythorpe plant in central England, threatening a repeat of a national wave of wildcat strikes at oil refineries, gas terminals and power stations in sympathy with the dispute at Total's Lindsey refinery.