The number of families who will spend Christmas in emergency housing is at a 10-year high, Shelter said.
The homelessness charity has launched an emergency appeal after an inquiry into the "shocking conditions many homeless children will be living in this Christmas".
Their report, which focused on those living in local B&Bs, concluded: "The majority of the families were living together in one room, while in over half of the cases investigated, children were sharing beds with their parents or siblings.
"Two thirds of families said that their children had no table to eat meals on, and often had to eat on the floor or on the bed."
One mother told Shelter she was "scared" for her son after being evicted by their landlord and relocated to temporary accommodation in Hounslow, west London.
Joan, a GP receptionist from London, said of her boy, seven: "It's so hard to give him a balanced diet as it's impossible to make proper meals here, let alone a Christmas dinner. He's getting really pale and is so tired all the time. He gets so scared but it's difficult when I'm scared myself. This is no place for a child to live."
Her son added: "Sometimes it's scary. There's no room to play here and I miss having my friends over."
Housing Minister Kris Hopkins said almost £1 billion had been given to tackle homelessness.