Tomáš Janoušek (nprofile…7dgh) yes, I was a member while employed in the UK.
They were very helpful with some small employment disputes, helped negotiate a raise, and got me a better deal with my redundancy.
In the UK, a Trade Union is a bit like having a lawyer on retainer. You pay a monthly subscription and get access to all the help and advice you need.
They also run campaigns and workshops which you are free to attend or ignore.