Indonesia has been hit by yet another tsunami - washing away at least 20 villages and leaving hundreds dead and many more missing.

And all this despite an expensive Tsunami early-warning system. As the waves surged towards the coastline, the system failed to work and no warning was given.

Indonesia's disaster response agency says the system had been vandalised and was not properly maintained.

As the death toll continues to rise, we ask why the system did not work.

Inside Story, with presenter Darren Jordon, discusses with guests: Amelia Merrick, the national director for World Vision Indonesia; Flemming Konradsen, the deputy head of studies in disaster management at the University of Copenhagen; and Tristan Robinson, a lecturer in environmental engineering at University College London.

This episode of Inside Story aired from Thursday, October 28, 2010.