Onora O'Neill reflects afresh on questions of trust, a decade after her Reith lectures on the subject. She argues that rather than asking, "how can we restore trust" in general, following recent scandals and failures, we should ask specific, practical questions about how better to measure trustworthiness. "Placing and refusing trust intelligently is not a matter of finding guarantees or proofs; we often have to assess complex and incomplete evidence, which the masters of spin and PR may be massaging to make things look better than they are." Systems of accountability or transparency can be ineffective or even counter-productive whereas easily assessable communication is "important and often indispensable." Producer: Sheila Cook.