A British aid worker being held hostage in Afghanistan was killed by captors during an attempt to rescue her, Foreign Secretary William Hague said today.
Linda Norgrove, 36, originally from Sutherland in the Scottish Highlands, was kidnapped by militants in Kunar province on September 26, alongside three Afghan nationals.
A decision was made yesterday to send troops in to free her "given the danger she was in", Mr Hague said in a statement.
It is thought that no British forces were involved in the rescue attempt.
A former United Nations employee, Ms Norgrove was working for the firm Development Alternatives Inc at the time of her kidnap.
Based in Jalalabad, she supervised reconstruction programmes in the eastern region of Afghanistan funded by the US government.
She was abducted by insurgents as she travelled in a convoy of two vehicles in Kunar province.
Local police chased the kidnappers but lost them after a brief firefight.
The three Afghan nationals were released last week, but Ms Norgrove continued to be held amid growing concern for her life.
Mr Hague said today that allies were tipped off where the Scottish hostage was being held and that "given the danger she was facing, her best chance of safe release was to act on that information".
But insurgents killed Ms Norgrove during the attempt to free her.
Mr Hague said: "Responsibility for this tragic outcome rests squarely with the hostage takers.
"From the moment they took her, her life was under grave threat. Given who held her, and the danger she was in, we judged that Linda's best chance lay in attempting to rescue her."
The Foreign Secretary added that Nato allies and Afghan authorities did all they could to save her life.
He added: "It is a tragedy that Linda was taken whilst doing the job she loved in a country she loved.
"Our thoughts are with her family and friends at this terrible time."
From an early age, Ms Norgrove got a taste of living in developing countries.
Her family would travel to third world nations for five weeks every second winter.
After studying at universities in the UK and Mexico, she became an environmental specialist at the World Wildlife Fund in Peru, before working for the UN in Afghanistan and Laos.
At Development Alternatives Inc (DAI) she worked with a team of Afghan professionals to strengthen local leadership and economies in vulnerable areas.
Prior to the kidnap, an attack was launched on the company's offices in Kunduz, northern Afghanistan.
The incident in July resulted in the death of a British private security guard.
Shaun Sexton, a 29-year-old former member of the Parachute Regiment, was one of four men killed in the blast.
Ms Norgrove is the second British aid worker to be killed in Afghanistan in recent months.
In August, Dr Karen Woo was shot dead with nine colleagues in Afghanistan.
They were returning from delivering medical supplies to poor Afghans in remote mountain communities, in an expedition organised by Kabul-based Christian charity the International Assistance Mission.
It is understood that seven insurgents were killed in the failed attempt to rescue Ms Norgrove.
Scotland's First Minister today conveyed his condolences to Ms Norgrove's friends and relatives.
Alex Salmond said: "This is extremely sad and upsetting, and I extend my deepest condolences to Linda Norgrove's family and friends at this heartbreaking time.
"Ms Norgrove was a dedicated aid worker who was doing everything she could to help people in Afghanistan - hopefully that legacy of service in a humanitarian cause can be of some comfort to her loved ones in their time of grief."
Local politicians also praised the contribution she made to humanitarian efforts in Afghanistan.
The SNP's Western Isles MSP Alasdair Allan said she was "a credit" to the local community "and the humanitarian cause which she served so well".
He said: "Our thoughts are with her family and friends at this sad and distressing time."
Western Isles MP Angus MacNeil, also of the SNP, added: "I am sorry to hear this terrible news and I'm sure the entire local community feels the same.
"Ms Norgrove was in Afghanistan trying to help and her death is an absolute tragedy."
Ms Norgrove spent her childhood on the Isle of Lewis, the first five years in Ness until the family moved to Mangersta in the Uig district. The family have a croft and kept cattle and other small livestock.
Mangersta was in the news recently when it emerged that the crofting community of less than 30 residents had begun a process of taking over the land on which they live.
The residents reportedly set up a company named Urras Mhangurstaigh to promote a buyout of the village and its common grazings, which cover 9,000 acres.
DAI President and CEO James Boomgard described Ms Norgrove as a "wonderful woman" and an "inspiration".
In a statement, he said: "This is devastating news.
"Our first thoughts at this moment are with Linda's immediate family: her parents, John and Lorna, and her sister Sofie.
"On behalf of all DAI employees, I extend to them our heartfelt condolences for their terrible loss.
"We are saddened beyond words by the death of a wonderful woman whose sole purpose in Afghanistan was to do good - to help the Afghan people achieve a measure of prosperity and stability in their everyday lives as they set about rebuilding their country.
"Linda loved Afghanistan and cared deeply for its people, and she was deeply committed to her development mission.
"She was an inspiration to many of us here at DAI and she will be deeply missed."
A spokesman for DAI praised her devotion to helping developing countries, adding: "She was in every respect a gifted development practitioner and an emerging leader in her field.
International Security Assistance Force Commander General David Petraeus said: "Afghan and coalition security forces did everything in their power to rescue Linda.
"Linda was a courageous person with a passion to improve the lives of Afghan people, and sadly she lost her life in their service.
"Our thoughts and prayers are with her family during this difficult time."