1 / 10Neither Louise nor Martine Fokkens fit the stereotype of a window prostitute in Amsterdam. The majority of women working in the most notorious public brothel scene in Europe are young, conventionally attractive and from outside of Holland. 2 / 10The Fokkens are 70-year-old identical twins, and very Dutch. Known as the 'oldest window girls' in Amsterdam, Louise and Martine have almost 100 years' experience of prostitution between them.3 / 10They have been the subject of a well-received film aptly named Meet the Fokkens and have written a book about their lives, due to be released later this month.4 / 10I travel to meet the twins and to be given a guided tour around the legalised sex industry that attracts thousands of British sex tourists every year. The sisters dress and speak identically, and, to complicate matters, often talk over each other, in a way that is almost impossible to understand. They seem to speak in a kind of code. But they are warm and eager to talk to me.5 / 10'I was beaten on to the streets by my husband in my early 20s,' Louise tells me when we meet in a tapas bar on Warmoesstraat, in the heart of the red-light area. 'He told me unless I earned money for him he would leave me, and I had children and loved him, so I had to do it.'6 / 10Louise has three children, and some or all have been in and out of foster care. It is difficult to get the exact story because Martine, who has four children, interjects with tales of losing her own offspring and the heartache that ensued. 7 / 10 It could be that one tells the story for both, or they tell each other. But both have encountered violence, abuse and exploitation, and their early years in prostitution were hard. 'We kept each other company,' says Louise. 'But Martine needs to carry on because there is not much money around.'8 / 10Louise, who left prostitution two years ago due to arthritis ('I could not do sexual positions') tells me how things have changed for the worse since she entered the sex trade. 'There are few Dutch women and no sense of community these days,' she says. 9 / 10When Louise began working, Martine was in hospital having her first child. 'My mother came in and said, 'You know Louise is [in prostitution]. I was in shock. I wanted to help her.'10 / 10'Later on they needed a cleaner in the brothel and Martine took the job and the men asked her for business,' says Louise. 'So we started doing threesomes, and that was how we ended up working in the same house [window brothel] together.'