Smartphone Sheriff app in South Korea

Many parents would like to know exactly what their children are up to, especially when they are online.

And there are plenty of apps to keep track of the websites young people visit on smartphones.

But South Korea has made having one of these apps compulsory for anyone under 19 who buys a new smartphone.

And the government has developed its own app called Smart Sheriff.

Is this Big Brother-style invasion of privacy or a genuine attempt to protect children online?

Stephen Evans reports.