Prime Minister Gordon Brown today hailed "the greatest of courage" of a soldier killed in a raid to free a kidnapped journalist.
Announcing the death with "very deep sadness", Mr Brown said his thoughts were with the soldier's family and said his bravery would not be forgotten.
The Premier said hostage-taking could never be justified and vowed when British nationals were taken the the UK would do "everything in our power" to free them.
Last night's operation was planned extensively and showed the Armed Forces had the "skill and courage" to act.
He added: "They are truly the finest among us, and all of us in Britain pay tribute to them, and to the families and communities who sustain them in their awesome responsibilities."
Mr Brown said in a statement: "Last night, Stephen Farrell, a journalist of dual British/Irish nationality, was freed from Taliban captivity in a British operation supported by the Afghan authorities and our Nato allies.
"He is now safe and well, receiving support from embassy staff and undergoing medical checks. Sadly, we were unable to rescue Stephen's Afghan interpreter, Sultan Munadi, and we send his family our condolences.
"It is with very deep sadness that I must also confirm that, while acting with the greatest of courage in this most dangerous mission, one member of the British armed forces lost his life. His family has been informed, and our immediate thoughts are with them. His bravery will not be forgotten.
"This operation was carried out after extensive planning and consideration. Those involved knew the high risks they were running. That they undertook it in such circumstances showed breathtaking heroism. I also want to thank the Afghan authorities and our Nato allies for their support.
"Hostage-taking is never justified, and the UK does not make substantive concessions, including paying ransoms.
"But whenever British nationals are kidnapped, we and our allies will do everything in our power to free them. As we all know, and as last night once again demonstrated, our Armed Forces have the skill and courage to act.
"They are truly the finest among us, and all of us in Britain pay tribute to them, and to the families and communities who sustain them in their awesome responsibilities."