Statistics have a habit of passing me by – not, I should stress, because I fall into that fashionable trap of disparaging number skills (no one boasts “I’m no good at English”, so why say it about maths?), but rather because I tend to need to hear a view expressed before it feels real to me.One statistic did pull me up short in the wake of the Charlie Hebdo murders. Some 40 per cent of French Jews, it was reported, were considering leaving the country because they no longer felt safe or wanted there. That’s a huge and hugely disturbing number, especially in a tolerant, liberal, democratic country that, in its revolution of 1789, was the first to grant Jews full civil rights after centuries of church-fuelled anti-Semitism. Perhaps, I wondered, it was something