It depends on you particular state and /or local laws. Generally 8 years old is acceptable for a short time such as between the end of the school day and your arrival home from work. But check your local regulations to be sure. You could simply call the police and ask them, then you will know the real deal.

In England i believe its 13yrs of age

From ExpertLaw.com: You can check with your state's Department of Social Services to see if your state has a minimum age for leaving children unsupervised. You are likely to find that there is no specific age, although the common recommendation is that children under twelve be provided with appropriate supervision while their parents are away from home. There may also be a suggestion that an older sibling, even if old enough to be left at home alone, is not necessarily an appropriate babysitter for younger siblings. There is good reason not to set a specific age at which children may be left at home alone. Specifically, no matter what age you pick there will be some children who are not sufficiently mature to look after themselves. It would not be good public policy to effectively grant parents immunity for the consequences of what they know to be poor parenting decisions, merely because a child has reached the age specified in a statute or regulation. Also, the nature and duration of the parents' absence can significantly affect the age at which the child should be left alone. A twelve-year-old may be perfectly comfortable taking care of himself after school until a parent gets home from work, but that does not mean that he's sufficiently mature to stay at home alone while his parents take a two-week tour of Europe.

In our state, it's 14, but they can not be alone overnight. We live within 11 miles of another state line, which is where I work/shop and I'm always nervous something may happen to my kids after school and I'll end up the Nancy Grace news show with her saying..."And this mother was out of state when this tragedy happened! What a horrible mother!" LOL!

There are very few states in the U.S. with legal minimum ages for children home alone, but many state agencies have published guidelines. Georgia, Illiniois, Maryland and Oregon are a few of the states with specific ages mentioned in their laws. 12 years of age appears to be the most common recommendation. http://www.latchkey-kids.com/latchkey-kids-age-limits.htm provides a state by state comparison with references. This site also provides one guideline from a California agency representative who suggests that 8 year olds and over can be left at home for up to several hours (usually after school before a parent gets home from work).