David Haines: PM says Britain will 'hunt down' IS killers

David Cameron says Britain will hunt down those responsible for the death of British aid worker David Haines.

Speaking after a Cobra meeting, the prime minister paid tribute to the 44-year-old "British hero" who was held hostage and killed by Islamic State [IS] militants.

He also said the country is "sickened" that a Briton could have carried out the "despicable" killing.

IS militants "are not Muslims, they are monsters," Mr Cameron said.