Do I have to tell my employer that I am taking industrial action?
No. It is often the case that management will send out emails/letters demanding that you declare in advance whether you will be taking industrial action. This can have the effect of misleading and intimidating members, and will enable your employer to minimise any disruption. You are under no obligation to inform management in advance as to whether you will be taking part in strike action or action short of a strike. UCU will provide your employer with all the information about the action required by law including those categories of members who we are calling on to take action. Once you are back to work following the strike action, you should respond truthfully to any query from your employer as to whether you have taken or are taking industrial action. You should not, however, respond to any such query while you are on strike. Info from UCU FAQ page