David Haines Beheading Video
A video purportedly showing threats being made to a man Islamic State (IS) named as David Haines by a masked IS fighter in an unknown location in this still image from video released by Islamic State September 2, 2014. REUTERS/Islamic State via Reuters TV

A day after reports came out that British Prime Minister David Cameron will announce next week the country's support to air strikes over Syria and Iraq initiated by the US, British Foreign Secretary Philip Hammond admitted on Tuesday that the country couldn't rescue a citizen whose head is being threatened to be chopped by the extremist group.

Read: Islamic State: British PM Cameron To Call For Air Strike After Militants Beheaded David Haines

Hammond acknowledged the failure of the British intelligence service to locate Alan Henning whom Islamic State (IS) militants threatened to decapitate after it beheaded David Haines, a British aid worker, on Saturday.

"We have considered every possible option to support these kidnap victims both British and other - and if we knew where they were, it would be a different story but we don't know where they are," The Independent quoted Hammond.

Henning is a taxi driver kidnapped by IS rebels from a charity aid convoy in Syria. Like Haines, Henning was in the country to offer his help, particular his cab driving skills to be a part of a 20-car convoy to Syria covering 4,000 miles to bring medical supplies to refugees affected by the prolonged civil war. Masked gunmen halted the group after it crossed the Turkish border on Dec 26, 2013 and immediately targeted Henning who joined Muslim friends in the road trip.

Read: Islamic State: Extremist Group Beheads Brit Aid Worker David Haines; Another UK Citizen Alan Henning Next In Line

The 47-year-old cab driver from Salford, Greater Manchester, left his wife Barbara and two teenage children during the Yuletide holidays to join the driving mission in Syria upon the invitation of a fellow cab driver, Kasim Jameel.

Jameel described Henning to the Guardian as a "normal bloke" who "wanted to do good." Henning was supposed to be in Syria for only six months, but he was abducted just a few days before his scheduled departure date.

It was actually Henning's second time to drive vehicles for the volunteer group Aid 4 Syria and the UK Arab Society, according to BBC journalist Catrin Nye who had encountered the cab driver while making a documentary about the Syrian convoys.

Nye said that Henning's first stint was a life-changing experience as he not only drove the trucks but also assisted in distributing the relief goods and held the children in refugee camps that he decided to return for the second time. The experience was etched not only in Henning's heart but also on his skin as he had the words "aid for Syria" tattooed on his arms.

YouTube/the rango