Every Friday, Lada leaves her small apartment to take tourists around Prague's underworld. "I pass on my cautionary tale," said the 54-year-old sex worker as she chain-smoked her way up the central Wenceslas Square. "At least my ruined life can be useful.

I can make a clean breast of it. It's a relief." Lada, who was homeless for years, is one of six tour guides who work for a social enterprise called Pragulic tackling "myth and prejudice" around people who live on the streets of the Czech capital.

Prague was infamous for its criminal underworld and drug problem in the 1990s. It still has a substantial homeless population of around 4,000, according to its social services. "We are trying to open people's eyes," Pragulic's Petra Jackova told AFP, "and teach them how someone may end up on the street.

The dividing line is sometimes very thin." For 12 years Pragulic's tours have been giving homeless people a voice and a chance to get a foothold back in society. "It's a therapy of sorts for them -- some have forgotten fragments of their lives and here they can put their memories together," Jackova said.

Some guides have quit after paying off their debts and settling down elsewhere, while others are close to doing so. Lada, who once lost everything to drugs and slot machines, does one tour a week to earn 400 CZK (16 euros, $17) plus tips. She still works as a sex worker to make extra money.

But now that she's clean of drugs for four years, the avid reader would like to quit. "I only.