A videotape posted on Islamic website tonight purportedly showed a man who identified himself as British hostage Kenneth Bigley pleading for Prime Minister Tony Blair to help save his life.

British hostage Kenneth Bigley’s life was tonight in the blood-stained hands of a terrorist who has severed the heads of two other captives.

The militant group led by al-Qaida ally Abu Musab al-Zarqawi has posted a gruesome video on a website showing the decapitation of a man identified as American civil engineer Eugene Armstrong.

Al-Jazeera television today aired video footage which it said was of a British and two American hostages.