London: Living for years on a bench

Is it OK if someone wants to live for years on a bench? Tom de Castella, BBC

"In 2017, freelance writer Tom de Castella noticed an elderly woman and her son living on a bench in south London. He discovered they had already been there for two years… which was puzzling. Why hadn't anyone done anything to help them? Why did everyone accept it as normal? The more he investigated, the stranger it seemed".