Industrial action is when workers:
go on strike
take other action, like refusing to do overtime (known as action short of a strike)
Sometimes an employer may stop their workers from working or coming back to work during a dispute. This is called a lock-out.
Calling industrial action
Industrial action happens when trade union members are in a dispute with their employers that cannot be solved through negotiations.
A trade union can only call for industrial action if a majority of its members involved support it in a properly organised postal vote - called a ballot.
Before organising a ballot, a union must decide which members affected by a dispute it wants to ask to take industrial action. It must tell all members entitled to vote and the employer what the ballot results were.
A trade union calls industrial action by telling members and the employer when and how this action will be taken. This should be done by a trade union official or committee that has the legal right to do so. Your voting paper must have said who this is.
Taking part in industrial action - your rights
If you are a trade union member, you have the right to vote before your union asks you to take industrial action. You do not have to take part in industrial action and cannot be disciplined by your union if you do not.
If you do get excluded or expelled from your union, you can complain to an employment tribunal.
It is against the law to take part in secondary action (going on strike in sympathy with people who work for a different employer).
For further information on Industrial action and strikes, see GOV.UK's website.