One eyewitness in Norwich said they were stopped from entering the building by HMRC personnel and that officers were posted on each floor.
“I walked in in the morning when I was greeted on the staircase,” they said.
The witness added: “They asked me: ‘Who are you? Where do you work?’ and told me that I couldn’t go upstairs.”
“In the nicest way possible, they were like rats all over the building,” they said.
Another described how they saw at least ten officers who had arrived at 07.30 BST and remained at the premises all day.
