Four foreign hostages abducted in Nigeria's volatile Niger Delta region within the last month have been freed.
Foreigners are targetted for ransom kidnappings by militants
A BBC correspondent says the sudden release of the British oil worker, Dutch security manager and two Lebanese construction workers was a surprise.
Nearly 70 foreigners have been kidnapped this year in the oil-rich but impoverished southern Nigerian area.
Their release means no hostages are currently being held in the Delta ahead of elections due later this month.
However, Chinese hostages snatched from a car assembly plant in the south-eastern town of Nnewi in nearby Anambra State, are still being held.
There is speculation that the release may be connected to the elections.
Jonathan Goodluck - the governor of Bayelsa State in Niger Delta - is the running mate to the ruling party's presidential candidate.
He has been campaigning on the slogan: "End to hostage taking".
Last month, the European Union said it would not be sending monitors to the Niger Delta for the polls as the region is too dangerous.
The BBC's Abdullahi Kaura in Port Harcourt says kidnappings for ransom are common in the Niger Delta and hostages are usually freed after ransom payments
The British national, Gordon Gray, who worked for Scotland-based Dolphin Drilling was taken by armed men from the Bulford Dolphin drilling rig in the Niger Delta early on Saturday.
"He was released along with a Dutch national and two Lebanese hostages who had been kidnapped as well," a Dolphin Drilling spokesman told AFP news agency.