DUBAI —A British warship tried but failed to prevent Iran’s Islamic Revolutionary Guard Corps from seizing a British tanker in the Strait of Hormuz last week, intercepted radio communications show, fueling a wave of recriminations in London on Sunday over who was to blame for the incident last week. In recordings obtained by the shipping consultancy Dryad Global and posted on its website Sunday, a member of the Revolutionary Guard is heard ordering the British-flagged Stena Impero tanker to divert course toward Iran. “Alter your course,” the man says. “If you obey you will be safe.” A British naval officer...