THE family of the Scots aid worker being held hostage by Islamic State militants is under 24-hour police protection in Croatia, it emerged yesterday.

David Haines, 44, who is being held by IS militants in Syria, has a wife and four-year-old daughter who live near Zagreb,

Haines was threatened with death in the recently released video of the beheading of US journalist Steven Sotloff.

He was shown in an orange jumpsuit kneeling below an English-speaking masked militant known as Jihadi John.

His wife, Dragana Prodanovic Haines, 44, spoke of their ordeal saying: "He's everything to us. He's our life. He's a fantastic man and father.

"Nobody can understand how we are feeling. My daughter keeps asking about him every day."

Foreign Secretary Philip Hammond has said that the UK Government would do everything it could to protect Haines. He said that Britain would not be diverted from "doing what is right by the threats that this organisation is making".

Hammond added: "We have to be clear about the nature of the organisation that we are dealing with.

"They are utterly brutal, they are ideologically driven, almost pathological in the way that they behave.

"We cannot allow our strategy to be driven by their behaviour.

"We have to approach the challenge of [IS] with focus purely on what is in Britain's best interests - protecting our citizens and our security from the threat that [IS] poses from foreign fighters, from potential attacks on our soil, destabilisation of the region."

Hammond spoke out after it was reported that the family of Haines was concerned air strikes against IS in Iraq would place him in jeopardy.

Yesterday, Syria carried out air strikes on Raqqa, Islamic State's stronghold some 250 miles northeast of Damascus.

Raqqa is believed to be the place where IS has kept its hostages, including Americans James Foley and Steven Sotloff, who were both murdered by their captors, as well as David Haines.

Haines also has a teenage daughter in Scotland from a previous marriage.

He was educated at Perth Academy secondary school and has worked for aid agencies in some of the world's worst trouble spots, including Libya and South Sudan.

He was posted to a refugee camp just inside the Syrian border by French charity Acted in March 2013, but it lost contact with him after he was seized by a gang. His Italian colleague, Federico Motka, was taken hostage at the same time, but released months later amid reports the Italian government had paid a ransom.

Acted has issued a statement calling for his release which described the threats on his life as "intolerable".

It said: "David has been working as a humanitarian since 1999, helping victims of conflict in the Balkans, Africa and the Middle East.

"When he was taken hostage in March 2013, David was in Syria as part of Acted's humanitarian effort in support of tens of thousands of people affected by the crisis.

"We have been mobilised from day one with David's family.

"More than ever, we are pursuing our efforts, and our thoughts are with David and his family."