A picket line is where workers and trade union representatives stand outside a workplace to tell other people why they are striking.

Employees taking part in strike action can join a picket line at their workplace. This includes:

trade union members

employees in the same 'bargaining unit' as the trade union members – this is the group of employees represented by the trade union

Trade union officials can also join a picket.

It's up to the person entering the workplace to decide whether they want to cross the picket line.

Picketers must allow people to enter the workplace if they want to.

If an employee is part of the bargaining unit represented by the trade union, they can decide to either:

cross the picket and continue working

not cross the picket and strike

If they work from home or another site, they might not have to cross the picket line. But they do need to decide whether to strike or not.

Find out who can take industrial action

Other people can cross the picket, including:

employees who are not eligible to strike

anyone needing to deliver goods or services to the workplace

If they decide not to cross the picket, this is called 'secondary' or 'sympathy' action.

Secondary action is unofficial action. If someone takes this action they are not protected by industrial action law. However, they'll still have their usual employment rights.

Find out more about unofficial action

Employees can picket outside a workplace that shares an entrance with other workplaces not involved in the dispute. In this situation, the picket line should not affect anyone going to the other workplaces.

By law, people taking part in a picket can peacefully:

talk to people wanting to enter their workplace

explain why they're striking

ask people not to cross the picket line

Picketers must not:

block or stop anyone entering the workplace or doing work

stop any vehicles entering the premises

threaten or abuse anyone

The full rules on picketing are covered by the picketing Code of Practice on GOV.UK.

Each picket must have a supervisor appointed by the trade union organising the picket.

The supervisor is responsible for the people on the picket following the rules. They must be at the picket, or available to attend at short notice.

Talk to the picket line supervisor if:

you're picketing and want to check what to do on the picket line

you have any questions about the picket line

you feel there's an issue with the picket line

As a picket supervisor, you can: