This is a dispute that says much about the age we live in, involving as it does yobs on a train, Twitter, two figures from very different versions of left-wing politics and, ultimately, libel lawyers.
First, the protagonists.
In one corner is Paul Embery (Twitter followers: 119,000), a firefighter, trade unionist, author of Despised: Why the Modern Left Loathes the Working Class, and supporter of what you might call traditional working class values.
