Lord Browne, BP’s chief executive, must give sworn testimony to be used in the death and injuries cases against the UK oil giant arising from last year’s fatal explosion at its Texas refinery, a judge ruled on Monday.

State Judge Susan Criss ruled that Lord Browne and John Manzoni, BP’s chief executive for refining and marketing, had “unique and superior knowledge” requiring them to undergo questioning, under oath, by plaintiff’s attorneys in the US.