The talks are with Abu Qatada -- a radical cleric of Palestinian-Jordanian descent and a Jordanian citizen -- who was once described by a Spanish judge as bin Laden's "spiritual ambassador in Europe."
Johnston, who turned 45 Thursday, has been held since he was kidnapped March 12 in Gaza City by Palestinian gunmen. His alleged kidnappers have demanded Qatada's release from Longlartin Prison in Britain.
Qatada is awaiting deportation to Jordan after the British government accused him of raising funds for extremist groups and offering "spiritual advice and religious legitimacy" to militants planning attacks.
"We have been in discussion with Abu Qatada via his lawyer with regards to making an appeal for his release," said a Foreign Office spokeswoman, who spoke on condition of anonymity in line with government policy.
The British Broadcasting Corp. said in a statement that it welcomes "any assistance from any individual who might be in a position to influence the release of Alan Johnston."
The case against Qatada was seen as the first real test of Britain's plan to deport terrorist suspects to countries with poor human rights records, after securing guarantees that those deported will not be tortured. Opponents claim the agreements, which are not binding, offer no protection to suspects.
His appeal of his deportation was refused in February. Qatada's lawyer, Gareth Peirce, said she would appeal again.
Qatada -- also known by his real name, Omar Mahmoud Mohammed Othman, and as Omar Abu Omar -- has denied supporting terrorism and claimed he would not receive a fair trial if deported to Jordan, where he has been convicted in connection with two 1998 bombings. He has been jailed in Britain under anti-terrorism laws since 2005.
Palestinian security officials said they believe the group holding Johnston is the Army of Islam. It is unclear whether the shadowy Palestinian group has ties with al-Qaida.
The group released a 20-minute recording recently, demanding Qatada's release. A picture of Johnston's press card accompanied the recording.
By: The British government is in talks with an associate of al-Qaida leader Osama bin Laden to try to secure the release of kidnapped BBC correspondent Alan Johnston, the Foreign Office said Thursday.