Islamic State: The difficulties facing coalition air strikes

Islamic State (IS) fighters renewed their advance in the Syrian border town of Kobane on Wednesday, with the US warning that air strikes alone cannot save it.

As Newsnight's diplomatic editor Mark Urban reports, the air campaign by the US-led coalition is arguably inefficient, with planes based far away from their targets.

With limited intelligence of IS positions, only 90 of the campaign's first 949 missions resulted in attacks.

So what does the future hold for the campaign?