When a delegation of executives from five of the world's biggest oil companies led by Italy's Eniwent to Kazakhstan last week to seek to resolve a dispute at the giant Kashagan oilfield, they were met with news that the government had halted work on the development on environmental grounds and had launched a criminal inquiry into alleged tax evasion on equipment imports.

It was an inauspicious start to what Paolo Scaroni, Eni's chief executive, had said would be "friendly talks" about the future of Kashagan. Irked by surging costs and sliding production deadlines, Kazakhstan is demanding improved terms.