The former US president might well have obtained the release of the two American journalists held by the North Koreans.

But it is impossible to be confident that North Korea is suddenly going to change the policies that have resulted in its ability to explode a nuclear device

Optimists will point to the changed atmosphere since the election of US President Barack Obama, who has dropped the "axis of evil" talk of his predecessor, George W Bush.

And the fact that Bill Clinton has gone perhaps indicates a readiness by North Korea to discuss something wider than freedom for two reporters.

It was on Mr Clinton's watch as US president that an agreement was reached - though later abandoned - to freeze the North's nuclear weapons programme.

However, even if there is some movement - such as the North agreeing to rejoin the six-party talks on its nuclear activities - the question will be how long that change will last until the next reversal.