Could Derna's disaster have been avoided?

As a wall of water washed through the Libyan city of Derna, it took everything in its path.

What’s left, is a ghost town, where the number of missing exceeds the dead and overwhelms the living.

Now, feelings of shock and grief give way to anger, as those who are left, demand answers.

So, why did Derna’s dam fail to protect its residents? And who’s going to take responsibility?

From Libya, ITV News Correspondent Emma Murphy tells Lucrezia Millarini What You Ned to Know...