Porter is hosting a new investigative documentary about the sex industry - Gail Porter On Prostitution - which airs next Monday on Current TV at 10pm.
She told DS: "I'm a very emotional person so there were a few times that there were a few tears, and I did feel helpless in certain situations.
"I did a police raid on a brothel in Ipswich. The house was tiny. It was vile, absolutely horrible. She just got on a train and went away, their living conditions are shocking."
The 39-year-old added: "She tried to do prostitution for a few months to get some cash and get a job, but because of the law in this country, she was given a criminal record and 20 years down the line she can't get out of prostitution.
"She's stuck, and she's really strong, and she really broke down, and I can't do anything. It makes me think the law in this country is stupid."
Porter further claimed that government action will not put a stop to sex workers: "I don't take a moral stance, that's the wrong way of looking at prostitution. People are going to work in a sex industry, and that's not going to go away."