Russell Brand’s bad behaviour was “normalised” and he was sleeping with women “day and night”, his former personal assistant told the court on Monday.

Helen Berger, who worked for the comedian between June 2006 and February 2007, described the role as “one of the hardest jobs I did” and recalled he was always in his underwear when she went to his flat.

“When I went to Russell’s flat he was always in his underwear as he loved walking around in his underwear with no shirt on,” she said in a statement read to Southwark Crown Court by prosecutor Riel Karmy-Jones KC.

The assistant said the star had “non-stop energy” and it was “a lot to deal with” as she helped him manage a busy workload at the height of his fame, including a national comedy tour, TV shows, a BBC radio show, a Guardian column and writing a book, as well as press and media engagements.

“In addition to his busy work schedule, Russell always had an insane sexual appetite and was sleeping with people day and night,” the court heard.

She said she…