In a postal sorting office beside a bakery on an industrial estate in Jerusalem, hundreds of letters are carefully set aside for special delivery and treated with the respect accorded to sacred documents. The envelopes are variously addressed, but all are destined for the same place. And all are unanswerable, at least by man.

This is the Letters to God department of the Israeli postal service, where each year more than 1,000 letters are received and once every few months opened, folded and, in a ceremony overseen by a senior rabbi, squeezed into the cracks of the Western Wall, in Jerusalem's Old City. Some are from Jews, some from Christians, some from believers of other faiths.

One letter from Poland now in the post office is addressed simply: "God, Jerusalem, Israel;" another, from Australia: "Dearest God, Western Wall." One from Britain reads: "To a poor man in Israel;" another: "The Rabi Jesus, Tel Aviv."

They arrive in many languages. Most these days are written in Russian, but others are from Germany: "Gott, Klagemauer, Jerusalem"; Mexico: "Dios, Muro de los Lamentos, Jerusalem"; and France: "La Terre-Sainte." Some are more esoteric, like one sent from Ghana and addressed to "The Cult of the Calebs, Israel," or another from Indonesia: "To the mighty one YHWH Elohim, Jerusalem, Israel."

Inside, they hold heartfelt messages of sorrow, or grief, or religious devotion. A pair of letters in Hebrew are addressed: "To my dead mother," and "To my dead father." One postcard, sent from the United States, and addressed to "Dear Jesiu" said simply: "I love you. I think of you. I thank you." Beneath his signature, the writer had taped three nickels to the card.

Some seem to have been inspired by visits or pilgrimages to Jerusalem, others by television preachers.

One written in English and addressed to "Mr Christ (God), Care of Jerusalem, Israel," began: "I want to thank you very much for the opportunity to participate in your television offer regarding the Christian faith and for your counsel and awards." It contained a cheque for one US cent.

Others seem driven by fervent religious belief, like one two-page, handwritten letter sent from within Israel but written in English. Addressed to "Son of the Nun, Joshua Cult, Israel," it began: "Is it a crime to serve the last God?"

For the past 12 years Avi Yaniv, 66, has had charge of the Letters to God department and has tried to make sense of the mail that arrives each day.

"They come from depression, or stress or grief," he said. "They ask for healing of a family member, or to make peace between a man and his wife, or between Israel and Arab countries. Some want material goods. We call it the checklist: they ask for a good job, a good wife, a nice car, a lot of money."

He has two regular writers, one from Mexico and another from Belgium, who send letters every few weeks. But, under the rules of the postal service, Yaniv is not allowed to write back to them.

Regardless of the faith of the writer, each letter is eventually delivered to the Western Wall and, after some time, the cracks in the wall are emptied to make way for new messages, and the old ones are buried in sacred ground. "We believe the Western Wall is the closest place to God in Jerusalem," said Yaniv.

Although letter-writing is in decline, at least in the west, there has been no reduction in the number of letters to God. Yaniv has noticed a sharp rise in letters from Russia and the former Soviet states in recent years, a sign, he believes, of the new openness in their societies.

Occasionally there are letters from Jordan or Egypt, and once from Morocco, but letters from other Arab states are not received. Most letters are deeply personal.

"I had a letter from one person who didn't ask for anything from God. He just wanted to thank God for what he already had," he said.

"Another was from Russia from a lady writing to her dead father. She had an argument with him and wrote very difficult words about the way he had treated her. Another time we received a letter from a man who wrote to God after his wife passed away. He asked God to send his wife back to him in his dreams so he could see her once again. He missed her very much."