There is no minimum age at which children in the United Kingdom can be left at home alone. The NSPCC have recommended that children around the age of 12 are rarely mature enough to be left alone for a long period of time. They also suggest that children under the age of 16 should not be left alone overnight. Babies, toddlers and very young children should never be left alone.
While there is no legal minimum age for leaving a child unsupervised, it is an offence to do so if it places them at risk.