Why did Arlene Foster make the shock decision to step down as DUP leader?

Last week, Arlene Foster abstained in on a vote on banning gay conversion therapy. That decision snowballed this week into Foster being effectively ousted as leader of the Democratic Unionist Party following a letter of no confidence from a majority of the party's elected representatives. We're joined by BBC Radio Foyle's Dominic McGrath, who explains what led to this decision, who could take over as leader of the party, and what it all means for Northern Ireland's fragile political landscape.