A long-awaited inquiry into the death of Russian former spy Alexander Litvinenko opened with the revelation that the KGB agent turned Kremlin critic may have been poisoned with radioactive polonium not once — as authorities initially thought — but twice.

The death of Russian spy Alexander Litvinenko gives rise to issues of “utmost gravity” including allegations of state-sponsored assassination, the chair of a public inquiry has said.

A radical Islamist cleric — described by prosecutors as a key al Qaeda operative in Europe — cannot be deported from Britain to Jordan to face terrorism charges, judges ruled in the latest twist in a protracted legal saga.