Nigel Chandler was detained last month near the eastern town of Brega along with Americans Clare Gillis and James Foley, Spanish photographer Manu Brabo, and UK-based photographer Anton Hammerl.
The journalists were reportedly charged with entering the country illegally and given one-year suspended sentences by a Tripoli court. Yesterday, Chandler, Gillis, Foley and Brabo were brought to the Rixos Hotel in the capital city and told they were free to go.
No more is known at this stage about London-based South African photographer Hammerl, who was not released alongside the others yesterday.
There were reports in the South African press three weeks ago that Hammerl was alive and well in the detention of pro-Gaddafi forces.
Chandler's detention had not been previously reported alongside the other four. Reports yesterday linked the freelancer to the BBC, but the broadcaster said this morning that it had not employed him to work in Libya.
An online petition calling for the release of the journalists had gathered almost 35,000 signatures.
In March, four New York Times reporters described being blindfolded, taunted, and beaten during "days of brutality" at the hands of pro-Gaddafi forces.
March also saw the release of two BBC Arabic staff, who reported being detained, tortured and subject to mock execution while working in the country, and two journalists from Agence France-Presse and a Getty Images photographer who were detained for five days in Ajdabiya.