Police officers have been accused of ignoring the needs of menstruating women held in custody.
A report from the Independent Custody Visiting Association (ICVA) says women in England and Wales are often held in police cells without access to hygienic sanitary protection, and left unable to wash their hands after or shower for several days.
Women have also been recorded on CCTV while changing tampons.
The situation was further compounded, the ICVA said, because many women detainees were not able to speak to a female police officer, or there weren't enough on duty.
Joanne was sat in a south London cell when she realised she was on her period. After summoning up the courage to ask a male officer for a sanitary towel, he sniggered.
'I felt like it was a joke between them,' she told Buzzfeed. 'I was made to feel stupid; I was made to feel embarrassed by something that is actually natural. I felt ashamed.'
The ICVA, a Home Office-funded body that advises the government and police authorities about custody conditions, believes the way menstruating suspects are being treated in police detention could be in breach of human rights and equality laws.
In protest, they've called on Home Secretary Amber Rudd to take 'swift action' to address the problem.
'At its most stark, this can mean women left in paper suits without their underwear and without sanitary protection,' the letter said.
'No woman or girl should be left in indignity by police officers for want of a difficult conversation or an inexpensive box of tampons,' the letter to Rudd - which has also been sent to Women and Equalities Minister Justine Greening and David Isaac, chairman of the Equality and Human Rights Commission - continues.
One woman, the report says, was stripped of her clothing, was dressed in a paper suit and refused any sanitary protection.
'She was left in a state of vulnerability sufficient to cause concern for her wellbeing, bleeding in a paper suit, alone in a cell,' the ICVA said.
Sherry Ralph, the organisation's chief operating officer, said that custody suites 'typically only have one absorbency of tampon and towel available'.
The open letter calls for minimum standards around the needs of menstruating women to be added to Police and Criminal Evidence Act (PACE) codes, which custody staff must follow in custody suites across the country.
Katie Kempen, Chief Executive of the ICVA, described the situation as 'both dangerous and undignified'.
'We are aware of horror stories with women left to bleed out. We have seen completely inadequate sanitary protection and we have spoken to detainees who haven't felt able to ask for sanitary protection, choosing instead to 'make do' with what they have,' Kempen said. 'If we do not see change, this shocking situation will continue.'
Between 2015 and 2016, approximately 150,000 women were arrested. Many of those would have been processed through custody and spent time in a cell.
To improve the situation, the IVCA recommends a range of things, including introducing a female officer as point of contact for women detainees, a hygiene pack offered automatically (with a fresh pack offered after six hours), hand-washing facilities, and that CCTV monitoring should be pixelated (or alternative arrangements made to allow women to change in private).
The Home Office has said it is working with the ICVA and the National Police Chiefs' Council 'to understand where improvements can be made on this issue'.
