A Muslim cleric described as Osama bin Laden's right-hand man in Europe yesterday rebuffed British government pleas to intercede on behalf of kidnapped BBC correspondent Alan Johnston.

The Foreign Office asked Abu Qatada, who is awaiting deportation to Jordan to face terrorism charges, to make an appeal from prison for Mr Johnston's release.

But this was dismissed as "not serious" by Qatada, who said he was ready to travel to the city of Gaza with a BBC delegation to meet Mr Johnston's captors with the aim of getting him released.

Mr Johnston's 45th birthday yesterday marked his 66th day in captivity.

In a statement issued through the London-based Islamic Observatory Centre, Qatada said: "It is clear that the British government is not serious in getting (Johnston) freed and is heading towards his getting killed."

He is said to have issued the letter because the "British government has been trying to deal with me in an incorrect manner in the matter of Alan Johnston".

However, it is unlikely that Qatada - described by the government as a "significant international terrorist" - would be allowed to go to Gaza.

The cleric, who has been described as a "key figure" in al Qaeda, is currently in custody fighting extradition to Jordan.

A Foreign Office spokesman said: "We have been in discussions with Abu Qatada's lawyer to see whether he would be willing to make a humanitarian appeal for Alan Johnston's safe release."

Qatada previously made an appeal for the release of British hostage Ken Bigley, who was subsequently murdered by his captors.

The Special Immigration Appeals Commission ruled in February that Qatada could be deported to Jordan - where he has been convicted twice in his absence of involvement in terrorist plots - despite his legal team's arguments that he would face a flawed trial there.

He has spent most of the past six years detained in custody in the UK because the government regards him as a potential terrorist threat.

Around the world vigils were being held yesterday to mark Alan Johnston's birthday. He was seized at gunpoint on his way home in Gaza City on March 12.

His parents, who live in Argyll, sent messages of love and support to their son in a televised birthday greeting, recorded in the hope that he has access to TV or radio.

His anxious father Graham said: "We're all thinking about you all the time, constantly. It would be a much happier birthday if you were here with us today. All our fondest love, my son. Keep your chin up."

His mother, Margaret, added: "Happy birthday, Alan. We're missing you, obviously. I'm going over to Cairndow (Argyll) today for lunch with some friends and we'll all be thinking about you and wishing you were with us."

His sister, Katriona, also sent a message saying how much she missed him.

She added: "Don't worry about mum and dad, I'm keeping their spirits up as you know I can."

Family friend Iain Hosack also happened to be celebrating his birthday, turning 102 today.

He said: "I'm not having a party this year, Alan, but next year we'll have a party and you'll be there. All the best, old boy."

Army of Islam, a little-known group, has claimed responsibility for the kidnapping and demanded that Britain frees Muslim prisoners - specifically naming Qatada.

The BBC's world news-gathering department was holding a series of events in centres such as Teheran, Hong Kong and Moscow to mark Mr Johnston's birthday and keep his plight on the agenda.

The abduction of Mr Johnston has triggered appeals for his release from around the world.

He was recently named broadcast journalist of the year by the London Press Club for his work reporting from the Gaza Strip.