Poor sanitation is the biggest killer of children in the world but its effect has been underestimated and the issue looks set to be ignored by the Group of Eight this week, according to a new analysis.

A report published Monday by WaterAid, the UK-based charity, has found that lack of access to sanitation is likely to be the biggest single cause of the deaths of nearly 10m children under 5 years old annually, and in total kills about 2.4m children a year.