Efforts are continuing to free five Britons held captive in Iraq since May, with time of the essence.Their kidnappers have released a video demanding the withdrawal of British forces from Iraq, which was broadcast by the Dubai-based Al-Arabiya TV station.In it a hostage read a statement saying: "My name is Jason. Today is November 18... I have been here now for 173 days and I feel we have been forgotten."In the video the kidnappers accused Britain of plundering Iraq's wealth and demanded that British troops be pulled out within ten days. The clip was apparently filmed on November 18, but it was not clear when this deadline would fall.The footage included a warning that the hostage would be killed "as a first warning" unless Britain pulled out its troops, according to one report.The five Britons, who have not been named, were seized by about 40 gunmen wearing police uniforms at the Iraqi Finance Ministry in Baghdad on May 29.At the time Iraqi officials blamed the Mahdi Army, the militia controlled by the radical Shiite cleric Muqtada al-Sadr, for the kidnapping.But al-Sadr's followers have denied responsibility and suspicion has since fallen on Mahdi Army splinter groups, which the US believes are controlled by Iran.Four of the hostages were working as security guards for Canadian firm GardaWorld, and are believed to have been the bodyguards of the fifth man.Downing Street and the Foreign and Commonwealth Office (FCO) have condemned the release of the video, saying it would only distress the captives' families and friends.© Independent Television News Limited 2007. All rights reserved.