Most people in literature and the arts know only that Britains libel laws are different and much more favorable to the plaintiff than are ours. One can say, with some justification, that this is primarily because we have a First Amendment, and the UK doesn't. On its face, though, that doesn't explain the broad paranoia about libel in the British arts. If one were to look strictly at substance, their libel law is only marginally different from ours. For example, exactly what constitutes an "opinion" as opposed to a "fact" seldom influences the actual outcome of a dispute in the US; that it is not really an issue at all under UK law (contrary to some of the broader statements made by those who should know better) is not enough to create paranoia. The absence of a "public figure" doctrine in the UK goes some way toward explaining some greater concern over there, but not the outright paranoia.
No, this is really yet another instance of civil procedure wonks (like me) having an edge on the political science types who care only about "substance." In this context, procedure is the substance. First, and perhaps most obviously, the UK operates (largely) under a "loser pays the lawyers" system; so a plaintiff who prevails for £1 in damages can obtain his entire legal fees and costs, perhaps over £1,000,000, in additional compensation from the losing defendant. That's not an exaggeration, either; similar disparities have occurred in at least a dozen instances since I was stationed Over There, and that's just the result after trial—it doesn't include settlements. One might argue that "that's what insurance is for" with some justification. More than just "some" justification, in fact; but potential legal fees are certainly going to be a deterrent to the libel defendant, who will fear the cost of a Pyrrhic victory.
More subtly, though, and certainly of more influence, there's the procedural question of the burden of proof. Under US law, a libel plaintiff must prove that the defendant
- purposefully made a written or recorded communication
- falsely asserting a fact (or an opinion necessarily implying a false fact)
- that was received by person(s) other than the victim
- and could reasonably be believed to refer to the victim,
- thus harming the victim's reputation
Under UK law, the elements are the same, except… for one tiny little burden of proof. In that second element, a US plaintiff must prove that the communication was false; a UK defendant must prove that the communication was true. Under the old litigator's rule of thumb that the party with the burden of proof will lose 75% of the time on that issue in a contested matter, we've just shifted half of the defense wins under US law to plaintiff wins. In other words, in this country truth is a complete defense, because it negates the very basis for suit; in the UK, it is at best a comparative defense, and sometimes publishing a true statement can still constitute libel. And that's before one gets into epistomological questions of what evidence one would need to accept a given statement on a controversial issue as "true" or "false."
Even without the First Amendment, the UK system makes little sense, until one begins to look at who the libel plaintiff in the UK tends to be: A celebrity or member of the more-rigidly defined upper classes. That truth matters less to these people than their reputations says something extremely unfavorable about UK society; and, by implication in the context mentioned in the first paragraph above, about Mr. Starr—since, as someone who is not a member of UK society, his "reputation" shouldn't really be at issue for a book originally published elsewhere, that can be obtained through Amazon by any citizen of the UK.
In turn, this gets back to the moronic distinctions of "territory" in English-language publishing; but that's for another day. All we need understand here is that where a book is published actually matters more than its substance. Or, perhaps, whether the adjudicator is Richard Wattis or the Queen of Hearts.