ALEX Salmond and Gordon Brown have been added to the bill of the nation's largest book festival.

The appearances by the two politicians will provide the most direct opportunity for two of the biggest figures in the Yes and No camps in the independence referendum to engage in public debate at the Edinburgh International Book Festival.

On August 11, Mr Salmond will be in conversation with Sir Tom Devine, who retires as Professor of History at the University of Edinburgh this month and is the author of books including The Scottish Nation and Scotland's Empire.

And four days later, on August 15, Mr Brown will talk to Alistair Moffat, the writer, journalist and festival director who is the author of books including Bannockburn and the Faded Map: Lost Kingdoms of Scotland.

Nick Barley, director of the book festival, said: "The two events offer our audience an exciting opportunity to get to the very heart of the independence debate.

"Two of Scotland's leading historians and writers are joined by politicians who are deeply committed to contrasting visions of Scotland's future.

"Their dialogues will examine Scotland's constitutional question, and the nation's future relationship with the rest of the United Kingdom, from an informed, historical perspective."

Tickets are now on sale for both events and can be purchased from www.edbookfest.co.uk.

This year, with the theme 'Let's Talk' the EIBF will bring 900 internationally-renowned writers and thinkers from 47 countries around the world to its base at Charlotte Square Gardens.