Is it against the law for a carer to work alone?

today i was told by my manager that i would have to work my 6 hour shift alone as a carer on one floor. There are 8 residents on this floor, one with very bad dimensia, 3 are bed bound, one needs hoisting to the toilet etc, they all need help to go to toilet and with eating. I told her it was illegal so she said the qualified nurse would help with positioning, toileting and meal time. Is this legal? thanks.