Should parents still be supporting their children financially when they've left school?

When do children really leave home? Millions of adults are relying on money from their parents to pay basic living costs. A recent report says mothers and fathers hand out an average £175 a month per child to help them with standard expenses such as bills and rent. In these tough economic times is it still a parent's duty to look after their offspring no matter how old they are - or is there a time when they should be standing on their own two feet. And what age is it?