Bolton School v Evans - Whistleblowing and IT hacker  EAT
Disclosure of wrongdoing can be a "protected act". Other conduct, even if related to the disclosure, is not protected.
A teacher warned his employers that their IT system was insecure. Not being taken seriously, he hacked into the system to show them how easy it was to do (and told them). They sacked him. He won an unfair dismissal claim but the EAT overturned the ET ruling as he was sacked for hacking, not for making a protected disclosure.