The group was discovered drinking at work when their manager checked the live CCTV pictures.
Paul Gallagher, co-owner of Bolton's Definitely Maybe Bar, was surprised to see his staff donning Christmas hats and stealing merchandise.
The 42-year-old snapped a snapshot of the group drinking and posted it on social media.
They taunted Paul by putting their fingers up at the camera and placed a Santa hat on it so they could continue the celebration in secret.
‘I frequently monitor the CCTV to ensure everyone's safety,' Paul stated.
It was obvious when I logged on and saw them all dressed in Santa hats, tables set with gifts all around.
They had a Secret Santa, purchased each other gifts, and were entertained by one of our musicians.
‘We weren't asked. Because it was a Monday night, they decided to have an impromptu staff party.
A little cheeky, but I didn't mind. I just wanted them to stay sober for a busy week.'
Workers decided to organise a last-minute celebration because they feared their annual January Christmas party would be cancelled again.
One of the partygoers decided to taunt the two by sending them a video of the covered camera.
Paul decided to give them a chance, and the party carried on into the early hours.
It's wonderful to do it before Christmas,' Paul added. ‘I shared a photograph of them all to Facebook showing the CCTV footage knowing our clients would be thrilled to see them on the opposite side of the bar enjoying themselves.'
‘I laughed when I noticed they had covered the cameras, knowing they would soon relent and remove them.
‘I like to think folks got the humour in it and I'm glad they had fun after serving our clients all year.
‘The January party may not go forward due to projected constraints.
I think workers' concerns about their own futures are often disregarded, so it was good to see them relax and forget about it for a night.'