The BBC's first director general, John Reith, oversaw the establishment of the BBC's first international radio service in 1932.

He maintained that broadcasting should be a public service that enriches the intellectual and cultural life of the nation: to inform, educate and entertain.

In this spirit, each year the BBC invites a leading figure to deliver a series of lectures on significant issues of contemporary interest.

Called the 'Reith Lectures', these programmes are usually broadcast on the BBC's domestic speech radio station Radio 4. For BBC World Service's 'Free to Speak' season, we bring together a panel of former Reith lecturers to talk about the status of freedom of speech.

From BBC News: Read viewpoints from the panelists

Listen to the 'Reith Global Debate'

The debate is chaired by Gavin Esler and the panel are: Onora O'Neill, Jeffrey Sachs and Wole Soyinka.