Secret ballots start on Thursday which will see some of the ten candidates out of the race.
There will be more ballots next week to choose a final two who will face a run-off with the party's membership.
The next leader will also be UK Prime Minister and face the task of delivering Brexit.
Conservative MP Ian Duncan-Smith says he's backing the front-runner Boris Johnson because he's committed to leaving the EU on October 31st - even if it has to be on a 'no deal' basis.
IN: "On the...
OUT: ...preparedness."
DUR: 14 seconds
http://www.fsnradionews.com/feeds/0613tories-ids1.mp3