Captors holding five Britons in
The purported hostage, speaking clearly with a British accent, identified himself as 'Jason'.
He sat under a sign in Arabic identifying the captors as 'The Islamic Shiite Resistance in
A written statement featured on the video, aired on Tuesday, accused
The group did not say what would happen if the deadline was not met or when the countdown begins.
'Forgotten hostages'
"Jason" said: "Today is November 18."
"I have been here now for 173 days and I feel we have been forgotten."
No other hostage was shown in the video.
British officials have not released the names of the kidnapped men, and have requested their identities not be disclosed by the media.
The kidnapping took place May 29, when about 40 gunmen in police uniforms and driving vehicles used by Iraqi security forces kidnapped four security contractors and a computer consultant from an Iraqi finance ministry compound.
The video was posted as
British troops withdrew in September from their last base in
The hostage in the video identified himself as 'Jason'.