Foreign policy will become a defining issue as Jeremy Corbyn declares his opposition to air strikes against Isis.
This weekend marks four years since the start of the crisis in Syria.
War has been raging in Syria for nearly four years and much of the country is in ruins, yet Bashar al-Assad is still in power. And the view from the presidential palace is brightening.
In 2011, Rami Habib, a 43-year-old doctor from Leicester, flew to Syria. Since then, he has watched the revolution against Bashar al-Assad fall apart – but he won’t give up.
In Damascus, the war seems to have receded, and Bashar al-Assad looks more comfortable than ever.
The American political scientist and author once predicted that liberal democracy had won the battle of ideas. Now he says political Islam is not a serious threat to the west and we should not intervene in Iraq.
Jemima Khan writes from Jordan on the Syrian refugee crisis.
On 16 September, the northern Syrian town of Kobane came under siege. Since then, reports state that more than 150,000 refugees have flooded into Turkey.
Will a vote on action in Syria be next?
The PM believes that there is "no legal barrier" to action, but wants to "proceed on the basis of consensus".