The Harris Tweed Authority owns four certification trade marks, one dating back to 1909. The Harris Tweed Act 1993 empowers the court to grant an injunction (or, in Scotland, and interdict) against anyone dealing in non-authentic - "authentic" meaning hand woven, in the Hebrides, from virgin wool - "Harris Tweed". That's a powerful supplement to a certification trade mark, although there are no criminal penalties under the 1993 Act. It seems recent in time, at least to one of my age, but of course it predates the Trade Marks Act and the criminal sanctions introduced there.
The Authority has recently, according to The Lawyer, been busy extracting an apology from Zara, the fashion house, which had been marketing through its online arm a garment which it described using the expression "Harris Tweed". Not a good idea, though they seem to have got off with just making an apology. With a brand like that, the Authority has to be on-the-ball and ready to take