A VIDEO broadcast on Arabic television on Friday has reportedly shown the beheading of British hostage Ken Bigley. But the Foreign Office is still checking claims of the 62-year-old's murder.

The 62-year-old from Liverpool was murdered despite pleas to the terrorists holding him to show mercy says Sky News.

Militants in the Iraqi city of Fallujah say they believe Mr Bigley was killed on Thursday in the town of Latifiyah, 22 miles south-west of Baghdad.

The captive's family had begged Tony Blair to step in and attempt to secure his release.

Engineer Mr Bigley was abducted in Baghdad along with fellow construction workers Jack Hensley and Eugene Armstrong three weeks ago.

A news presenter in Abu Dhabi said on television: "We have learned from informed sources in the Iraqi capital that the kidnappers of Kenneth Bigley have killed him."

Mr Bigley's brother, Paul, said: "I have heard these reports and I am looking into them right now."

British embassy staff in Thailand said they were in "close contact" with his wife, Sombat.

The Tawhid and Jihad terrorist group beheaded the two Americans within a week and their remains were found in the Iraqi capital.

Abu Musab al Zarqawi, who ranks as one of Washington's most wanted men, is believed to have killed at least one of the Americans.

The men's kidnappers had initially called for the release of all women prisoners held in US-run prisons, but their demands later became more muddled.

The horrific alert comes just 24 hours after Iraq's interim prime minister, Ayad Allawi, said there were promising behind-the-scenes to secure Mr Bigley's release.

If the reports prove true, Mr Bigley would be the first British captive killed since Coalition forces invaded Iraq in March 2003.

Trade Secretary Patricia Hewitt said the Foreign Secretary Jack Straw and his colleagues at the Foreign Office were doing all they could.

She said: "Our top priority is to find out if the reports are true. We have to do everything possible and hope that they are not confirmed."

Ms Hewitt reiterated that the Government could not negotiate with terrorists.