Who will lead the ground offensive against so-called Islamic State?
On Wednesday, MPs will vote on whether or not to back UK air strikes in Syria against militants from so-called Islamic State, but there is broad agreement among politicians that IS cannot be defeated by such action alone.
The government says military action is "only one component of a broader strategy”, with David Cameron claiming that there are 70,000 "moderate" ground forces able to fight IS in Syria.
But some MPs have questioned whether all such forces can be considered “moderate”, and how effective they would be.
Video produced by Adam Eley.
The Victoria Derbyshire programme is broadcast on weekdays between 09:15 and 11:00 on BBC Two and the BBC News channel.