Do I feel strongly enough about it to emigrate? The law as it stands in terms of freedom of speech has been much the same for centuries.
Please don't emigrate just yet—you may be in luck. The European Convention on Human Rights guarantees freedom of speech for all EU citizens. It was enshrined into UK law by the Human Rights Act in 1998; this was the biggest fundamental change in the law regarding freedom of speech for centuries.
The problem is, the way it is enshrined into UK law also introduces a significant number of restrictions, mostly around the areas of security, crime, and morals. But the government has to actually pass specific legislation to limit speech in these areas, and if these national laws fall short of the European Convention then they can be challenged in the European Court of Human Rights.
One of the weaknesses of the British constitutions is that most people—even most British people—seem to have been persuaded that we don't have one, so few people are willing to stand up and fight against unconstitutional laws.
Far from free speech not being a vote winner, it looks likely that reform of our libel laws will become a significant issue at the next election, for example with campaigns like libelreform.org causing a lot of unrest in political circles.