Nuclear treaty still not in force after 20 years

The Comprehensive Test Ban Treaty Organisation marks two decades of existence this week, with a question mark over its future.

Nuclear treaty still not in force after 20 years

The Vienna-based organisation was created to enforce a ban on nuclear bomb testing but after 20 years the treaty behind it is still not in force.

Our correspondent in Vienna, Kerry Skyring, told Greg Dyett why it's taking so long for the nuclear test ban treaty to become legally enforceable.