When an improvement notice is served, the employer must take action to put things right within a specified time. Inspectors have the power to issue an immediate prohibition notice to stop an operation if there is a risk of immediate danger. They may also issue a deferred prohibition notice. Appeals against these notices go to an employment tribunal and can lead to a stay (delay) of execution of an improvement notice. There can be no delay in implementing a prohibition notice if the inspector believes the risk of serious personal injury is imminent.