In this episode of Frost over the World:

Nearly a year ago Morgan Tsvangirai was sworn in as prime minister of Zimbabwe in a new unity government with Robert Mugabe, the country's president.

However power-sharing has been far from straightforward and outstanding issues remain.

So what now for Zimbabwe's unity government? Tsvangirai joins Sir David from Davos to discuss.

Plus, representatives from all over the world gathered in London on Wednesday for a conference on Yemen. Sir David spoke to Abu Baker Al Qirbi, the Yemeni foreign minister, on the eve of the meeting.

From the shipyards of Glasgow to global megastar, Billy Connolly has been making us laugh for the past four decades. Now he is back in London, having taken up residence at the Hammersmith Apollo for his latest stand-up show.

James Appathurai, the Nato spokesman, talks to Sir David about the conference on Afghanistan and Nato's mission in the country.

Nasser Judeh, Jordan's foreign minister, talks to Sir David about Afghanistan and the progress of the Middle East peace process.

This episode of Frost Over the World aired from Friday, January 29.