Historian Dan Snow said they had wanted to choose a "run-of-the-mill day".

BBC: NEWS | Technology | Blog records Britons' daily lives

Historian Dan Snow, journalist and broadcaster George Alagiah and BBC weather presenter Heather Reid were among the guests on Saturday, the last day of the festival.

BBC: NEWS | UK | Scotland | Politics festival 'huge success'

Cerberus already counts several ex-government officials in its ranks: John Snow, a former treasury secretary, is chairman, and Dan Quayle, a former vice-president, heads its international arm.

ECONOMIST: Cerberus