The case makes it clear that when considering whether a request to bring a particular companion should be allowed at any stage of a disciplinary or grievance process, the duty of trust and confidence might require an employer to consider a potentially wider range of companions than that specified either by statute or even in the employee’s contract.

The inference that a class of companion should be allowed where this would not normally be the case, will often be strongest where ‘fitness to practice’ issues might flow from the outcome of the internal procedure, or the employer’s decision might seriously affect the employee’s ability to obtain further employment in their field.
You can read the case here: http://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWHC/QB/2015/2300.html
View our summary of the case here.