Well, they don't enjoy a
legal "right" (article 10 of the European Convention on Human Rights, which is incorporated into the British legal system, provides the right to freedom of expression,
subject to certain restrictions that are "in accordance with law" and "necessary in a democratic society". (my emphasis), but as a matter of everyday occurrence, people enjoy the freedom to "speak their mind" as long as they're prepared to accept the consequences of doing so, and "subject to certain restrictions", for example the "hate speech" legislation.
As I said, I'm perfectly happy for someone to call me a "Jew bastard", as long as they're prepared to take their lumps for doing so.