Sydney ABC radio presenter Richard Glover has wrapped up the world's longest radio or TV interview.

Glover interviewed journalist and author Peter FitzSimons from 10am yesterday. The duo finished the marathon chat 24 hours later at 10am today.

Slow baked ... Peter FitzSimons and Richard Glover on the way to setting an interview record in the ABC studios in Sydney. Credit:Courtesy of the ABC

The two discussed everything from Christianity and the flag to Kokoda, the Ballarat gold rush and the techniques of modern historical research.

The interview ended with Glover asking FitzSimons why he wore his trademark red bandanna.