A customer who visited a Burger King branch in Portsmouth said the conditions are "filthy" after spotting food all over the floors.
Kim Puddick went to the restaurant on Commercial Road on Tuesday 27 December.
Photos taken by Kim show chicken and fries strewn across the kitchen floor, as a member of staff stands amongst the food.
Wrappers and rubbish can also be seen on the tiles of the preparation and serving area.
Kim said: "Maybe it’s me but I couldn’t believe how people just ignored all of this and handed over money for food cooked in these conditions.
"I took these photos and left. If this is what you can see, imagine what goes on behind the scenes."
Online the restaurant has a mixed reception, with a rating of 3.3 out of 5 stars on Google.
One customer wrote: "Good quality fast food, friendly staff, clean tables and floor".
Whilst another visitor also commented on the state of the fast food store, saying: "Wow. Really. Absolutely disappointed and disgusted with the state of the place. Shocking. Food everywhere. Dirty tables. Not even busy. Had to clean my own table."
Meanwhile, another customer praised the staff at the branch. They said: "It was great customer service...staff behind the counter were really helpful. Overall I was impressed."
ITV Meridian has contacted Burger King for comment on the conditions.