Just this morning at work, we've been sent the new London Child Protection Procedures, 4th Edition (Dec 2010). 5.26 Left alone 5.26.1 The law is not clear because it does not state an age when children can be left alone. However, parents can be prosecuted for wilful neglect if they leave a child unsupervised ?in a manner likely to cause unnecessary suffering or injury to health? (Children and Young Persons Act, 1933). 5.26.2 Nor does the law state an age when young people can baby-sit. However, where a baby-sitter is under the age of 16 years, parents remain legally responsible to ensure that their child comes to no harm. 5.26.3 This is, in part, in recognition that all children are different and demonstrate different levels of maturity and responsibility. 5.26.4 In any situation where a child is left alone, consideration should be given to the context (e.g. the ages, needs and maturity of the children, the length of time involved, the frequency of such incidents, the safety of the location and any other relevant factors). Having taken into account the circumstances above, the key question to ask is was the child left to their own fate? You can find the full CP document here, but it's a long old document!