A Briton held hostage in Yemen for around 18 months is reportedly set to return to the UK after being freed.
The man, named by the United Arab Emirate's state news agency as Robert Douglas Semple, 64, was released in a military intelligence operation by the Middle Eastern country's forces.
He had reportedly been working as an engineer when he was kidnapped in February last year by al Qaida.
Prime Minister David Cameron said he was "so pleased" for the family of the Briton and thanked the UAE forces for the rescue mission.
He said: "I'm so pleased for the family of the British hostage in Yemen - who has been released safe and well. Thanks to the UAE for their help."
The WAM news agency said Mr Semple has spoken to his wife by telephone after being flown from Aden to the UAE capital Abu Dhabi and would return to the UK after having medical checks.
A video emerged on Sunday apparently showing Mr Semple pleading for help seven months after he was kidnapped.
Footage posted on YouTube by Arab broadcaster AlziandiQ8 on August 31 last year appears to show Mr Semple begging for help from Britain or Yemeni authorities, saying he fears his captors will soon kill him.
In the video the blindfolded man speaks haltingly with his head lowered, saying: "My name is Bob Semple. I am a British subject working in Yemen for a royal services company, Intracs Middle East Limited.
"Please, British or Yemen, please help me to get back to my family. I have been captive for seven months and my situation is not good. These guys are going to kill me, soon, I think.
"Please, act quickly for my release."
The footage has not been verified as authentic by British or foreign authorities.
Foreign Secretary Philip Hammond, who is in the Iranian capital Tehran, said the Briton was receiving support from UK officials.
He said: "I'm pleased to confirm that a British hostage held in Yemen has been extracted by UAE forces in a military intelligence operation.
"The British national is safe and well and is receiving support from British Government officials. We are very grateful for the assistance of the UAE."
Several Britons have been recently kidnapped in impoverished Yemen, where abductions are frequent as armed tribesmen and al Qaida-linked militants take hostages in an effort to swap them for prisoners or cash.
British-born American Luke Somers, 33, was shot dead by his Al Qaida in the Arabian Peninsula captors in December as they fought US special forces attempting to extract him and South African teacher Pierre Korkie.
He was kidnapped in September 2013 in the capital Sanaa while working as a photojournalist.
In July last year Mike Harvey was released five months after being captured in Sanaa.
His abduction was the third to take place in Yemen in only two weeks. On February 2 last year, another Briton working with an oil services company was kidnapped in Sanaa. Two days earlier, a German citizen was also kidnapped.
In April 2010 the then British ambassador to Yemen, Tim Torlet, escaped unharmed when a suicide bomber wearing a school uniform detonated an explosives belt as he made his way to work in Sanaa. The following October his deputy, Fionna Gibb, escaped a rocket attack in the city.
The UAE is involved alongside Saudi Arabian forces in combating the Iran-supported Shiite Houthi rebels and allied units of Yemen's fractured military as the country collapses into chaos.
Saudi Arabia began bombing military installations in Yemen in March after receiving a request for help from president Abed Rabbo Mansour Hadi, who left the country by sea as the Houthis pushed towards the port city of Aden.
The air strikes had the support of several other countries in the region, but were condemned by Iran as an "invasion" and a "dangerous step" that will worsen the crisis.
Saudi Arabia and its allies believe the Houthis are tools for Iran to seize control of Yemen, though the Houthis deny they are backed by Tehran.