It's a long way from the bimah to the picket line, but more and more rabbis are joining the trade union Unite.

The organisation now has 25 Jewish "faith workers" among its members - including at least 14 rabbis, according to Reverend Dr Mike Bossingham, secretary of Unite's clerical branch.

"That's more rabbis than ministers of the Church of Scotland or Baptist ministers," he said.

Unite's clerical branch has around 1,500 members, including three imams.

Rabbi Ariel Abel, of Princes Road Synagogue, an Orthodox shul in Liverpool, was co-opted onto the branch executive earlier this year to add a Jewish voice.

"Unfortunately, bullying and harassment of rabbis has not gone away," Rabbi Abel said.

"If I sit in the company of rabbis for more than a half an hour, I'll start to hear tales of woe. And that's a shame."

A typical example, he said, would be a rabbi "getting a nasty letter accusing them of malpractice when they have done nothing at all".

Or a rabbi facing a disciplinary investigation for not turning up to officiate at a funeral or stone-setting when "no one had actually informed him it was taking place".

Dr Bossingham recalls the case of one rabbi whose encouragement of children to come to services landed him in hot water with some congregants who complained that they were too noisy.

"You wouldn't believe it," he said.

"The main problem is the isolation ministers often feel. I think it is the same in all faiths. For Christian ministers, declining congregations are a problem and that puts pressure on finances."

But he pointed out that rabbis "do have a slightly different position in that they do have employment rights because they are recognised as employees rather than office holders."

Rabbi Abel said that some of his colleagues "worry that if they make a complaint about the way they are being treated, they are going to lose their jobs. But they believe erroneously that if they don't speak up, the problem will go away.

"I want to see rabbis happy in their jobs and working for the betterment of the entire community, not for one or two people on the board who may not like them. Rabbis must not be seen as punchbags.

"If it's OK to push a rabbi around, that is going to run down the rabbinate. They won't want to serve communities."

Rabbi Danny Rich, Liberal Judaism's senior rabbi, is also a member of the union.

He said: "In any relationship that is not of equal power, and the relationship between employer and employee is one such example, the weaker may sometimes need protection, and the trade union provides that."