Brighton have been urged to reinstate three members of staff sacked for allegedly leaking team news on social media by the employees' union.
GMB represents the club's ground-staff team and has accused Brighton of failing to follow any due employment processes to wrongfully dismiss staff without a hearing or right to appeal.
The sackings came after prolonged investigations of all the ground staff working at the club's Lancing training facility.
According to GMB, during a near three-month inquiry, Brighton safety and security manager Adrian Morris could not confirm to staff whether his investigation was following any formal process or was simply seeking their assistance to find the social media leak.
However, the investigation reportedly included the seizure of some mobile phones from staff to check and download content and usage, along with regular surprise interviews, none of which provided any links between the members of staff dismissed and the team selection leaks.
A letter from Brighton head of HR Rose Read states the club will be terminating employment without notice because they have lost all trust and confidence in the individuals, without providing evidence as to why nor their right of appeal.
Mark Turner, GMB branch secretary said: "The club may have retained Premier League status this year but it seems that it provides its hard-working staff Sunday League employment rights.
"No evidence has been found or presented by the club during this near thee month investigation which links our members to the supposed social media team leaks, yet they today summarily dismiss our members without notice.
"This just stinks and considering this club prides itself on its commitment to the standards, values and expectations set by the Premier League, along with professing to believe all forms of prejudice and discrimination are unacceptable, the way they have treated their staff throughout this witch hunt is simply deplorable and unfair."
Brighton are not commenting on the issue.