When I first visited Canary Wharf in the early 1990s, I was struck by a set of black-and-white posters in the shopping concourse advertising the Co-op Bank’s ethical banking stance: essentially, no lending to arms, tobacco, gambling or oil companies, or to regimes that disrespected human rights. A cynic might have argued that it was all about virtue signalling (before we learned that phrase) in the sense that no landmine manufacturer or brutal Third World dictator had ever been known to pop into a Co-op branch, ask for a loan and be met with a polite refusal and a copy...