The former Archbishop of Canterbury, Lord George Carey, has appealed for the release of five British nationals who have been held in Iraq since May 2007.

Five Britons - four security guards and one computer expert - were kidnapped from a finance ministry building in Baghdad by Shia militiamen in May by abductors dressed in Iraqi police uniforms.

In a video broadcast on an Arabic television station last week, the hostage-takers threatened to kill one of the men if British forces did not leave Iraq within 10 days.

Lord Carey made his appeal on Wednesday during the televised broadcast of a message he was delivering to the five men on behalf of their relatives.

"I would like to add my own personal appeal at this holy time of Eid and Christmas - this is a peaceful time which is important for Muslims and Christians alike - that we may be able to see the safe return home of these men as soon as possible," he said.

The message from the families stated: "We have been apart from you, our husbands, sons, brothers and fathers for over 6 months now and we hope and pray that you will be back home with us soon.

"It has been a difficult time for us all being apart from you, particularly at this time of the year. We love you and miss you very much and want you to know that you are never out of our thoughts."

In the message, family members made a heartfelt appeal to the captors to allow the men to hear the message and release them from captivity.

"We appeal to those holding you; please allow our loved ones to hear this message and let them know how much we love them. We know that you have the power to return them to us and we ask you to do so. We remain serious and committed to exploring all the options open to us to bring about their safe return," they stated.

On Sunday, Prime Minister Gordon Brown called for the immediate release of the hostages in response to the threat from the militiamen to kill one of the hostages.

"The taking of hostages is completely unjustified, wholly unacceptable and we are making it clear they will not change our policy in any way," Brown said.

"We will do everything in our power to secure our objective, which is the immediate release of the hostages."