John Bercow joins Lenny Henry and Lady Butler-Sloss as Today programme guest editors

Also curating shows are Everything But The Girl's Tracey Thorn and Lord King of Lothbury

His traditional role is to hold the ring but John Bercow will be the one posing the questions when the Speaker of the House takes his turn as guest editor of the Today programme.

Mr Bercow heads a line-up including Lady Butler-Sloss, the former president of the High Court Family Division, for the annual takeover of the Radio 4 programme’s hot-seat during the festive period.

Speaker Bercow takes the reins on Boxing Day when he will steer a programme which looks ahead to parliament’s 750th anniversary.

He will quiz Wikipedia founder Jimmy Wales on how to “retool the House for the digital era” and interview Burmese opposition leader Aung San Suu Kyi about Myanmar’s fledgling democracy.

Speaker Bercow will also grill his personal hero, tennis champion Roger Federer, about staying motivated in old age and pushy tennis parents.

Baroness Butler-Sloss, who guest edits on New Year’s Eve, is expected to avoid the “conflict of interests” controversy which forced her to resign as chair of the Government’s inquiry into historical child abuse this year.

She will visit Gibraltar to find out what the future holds for the British outpost. Her programme will also tackle how the media “misunderstands the countryside” and how stressful the life of a parish priest can be.

Lenny Henry will explore diversity on his 30 December show, featuring interviews with people who broke down racial barriers a generation ago. The comic actor asks how much more progress is needed in broadcasting, business and sport and will also look at comic books and the black literary canon.

The former Everything But The Girl singer Tracey Thorn will bring her musical influences to bear on her edition by paying homage to Kate Bush with her own cover of Under the Ivy. She will also look at how the internet can be a positive force for teenagers rather than a threat.

Lord King of Lothbury, the former Governor of the Bank of England, will examine social mobility in his broadcast and ask the vital question – are German footballers simply cleverer than English ones?

A Today programme guest-edited by PJ Harvey last year was dismissed as “left-wing tosh” by critics after the singer gave a platform to Julian Assange and journalist John Pilger.

Gwyneth Williams, Radio 4's controller, defended the “guest editors” initiative: “I think it’s a mixed bunch each year. This year’s line-up looks rather good to me, they should be different and varied. It’s definitely not Russell Brand.”