Sir Keir Starmer draws a narrow legal distinction. But if British bases enable a wider US-Israeli campaign, the UK risks sliding into an unlawful conflictIn the Commons on Monday, Sir Keir Starmer was clear that Britain will not join offensive action against Tehran. It is wise not to join an illegal attempt at “regime change from the skies”. Sir Keir will, however, permit US use of British bases for limited defensive strikes aimed at stopping Iranian missile attacks. That is a legally clear line, but it may be politically and militarily tricky to stick to.Donald Trump and Benjamin Netanyahu’s actions are reckless and unlawful. But so are Iran’s strikes – hitting hotels, airports and energy infrastructure – across the Gulf. Where Britain’s allies have asked for support, or where UK nationals are at risk, the UK is legally entitled to act in collective self-defence. But this holds only as long as the action is restricted to halt Tehran’s barrage.Do you have an opinion on the is...