In many Orthodox synagogues it is the custom, as the Saturday morning service draws to a close, to sing a 12th-century poem known as the Hymn of Glory.

Some worshippers may pay little attention to the meaning, happy to sing along in Hebrew as their thoughts turn to the imminent wine, cake and fishballs of the after-service kiddush waiting in the hall. But if they do dwell on the words, they will be struck by the boldly anthropomorphic imagery. God is compared to a youthful warrior whose “curls are filled with dewdrops of light/ His locks with fragments of the night” (in Chief Rabbi Sacks’s translation).

It is a vivid example of the way in which the deity in monotheistic tradition has invariably been spoken of and prayed to in masculine language. The linguistic legacy has left a deep imprint. In a recent Populus poll in the UK, 62 per cent of respondents thought of God as male, compared with just 1 per cent as female (with 18 per cent answering neither, and 3 per cent both).

But now the Movement for Reform Judaism, which comprises a fifth of British synagogue members, hopes to stake the claim for greater egalitarianism with its new prayerbook. A distinctive feature of Forms of Prayer, the first revision of its daily and Sabbath liturgy for more than 30 years, is the use of “gender-inclusive” language.

“King” is replaced by “Sovereign”, “Lord” by “The Eternal” and “Father of Mercy” by "Source of Mercy”. In the core prayer, the Amidah, God, previously addressed as “God of our Fathers” — the patriarchs — is now also “God of our Mothers” — Sarah, Rebecca, Rachel and Leah too.

It is not the first use of such language in the liturgy of British Judaism. The smaller and more radical Liberal movement got there first in 1995. In the same year the Reform used egalitarian terminology in a festival prayerbook — although, more tentatively then, it offered both traditional patriarchal and new inclusive versions of the Amidah as options, whereas only the latter appears in the new book.

Still, there was some rearguard resistance. The late Professor Alfred Moritz, a classical scholar from Cardiff, writing in the magazine Manna six years ago, complained of “Pocol”, politically correct language, having become “a hurricane sweeping all before it”. In his response in the same journal, the prayerbook’s editor, Rabbi Professor Jonathan Magonet, defended the work in progress: however accustomed one might be to a term like “Lord”, he wrote, “It nevertheless perpetuates the association between God and male authority within society.”

Innovation only goes so far, for the egalitarian language is more apparent in the English translation of the prayers rather than the Hebrew. Whereas English grammar can largely accommodate gender indifference, Hebrew, like French, divides its nouns into masculine and feminine, so that God always carries the pronoun “He”. But the vernacular will make its impact, since Reform and Liberals use varying degrees of English in services, unlike the Hebrew-only Orthodox. And even within mainstream Orthodoxy, many Jews, even if they pray in Hebrew, think in English.

For one of the Reform’s youngest rabbis, Miriam Berger, 29, the value of the new book is its capacity to help people to think. Her Finchley congregation has been using draft editions of it for two years. “For me the issue of gender-inclusive language is not really a feminist statement any more,” she says. “I’ve felt that generations of women rabbis who have gone before me have managed to fight those battles for me.

“I see the change in language as a theological statement that we are challenging people to really look at their relationship with God, to understand and grapple with the limitations that language puts on God and to help people through the issues where often I think liturgy has let them down, the issues of not-believing.”

Many people struggle with traditional appellations of God, she says, and that can become more acute in “difficult times. When I’m talking to people and they are sitting by hospital beds and watching someone dying, it’s then that they say ‘I’ve never been really able to believe in God and, look, this is the proof. How is there a king, a father or a judge who’s making this happen?’

“I think that often the language of how we refer to God can often be destructive in terms of people’s belief rather than constructive. I hope the new siddur (prayerbook) allows people to construct their own belief and their own concept of God.”

Rabbi Berger’s point, that language can open new religious possibilities, is one reason why traditionalists balk at change. Christian modernisers, for example, who have proposed recasting the Trinity as “Creator, Redeemer and Sustainer” rather than “Father, Son and Holy Ghost” have faced the argument that this formula represents a theological, rather than simply a linguistic, departure.

Whatever the difficulties, campaigners such as Ianthe Pratt, who chairs the Christian group, the Association for Inclusive Language, believes the search must go on. Through using a term such as “Father”, she says: “People tend to think that God must be male, whereas even in Catholic theology, it is recognised that God is spirit and hasn’t got a gender. And this is our problem. Some people don’t mind it, but I think a lot of women are very offended and sensible men are offended by it.”

She welcomes the new Reform Jewish prayerbook. “The more people of different faiths can help each other, the better,” she says. “It’s a long haul, but I’m a great believer that we should sow seeds and not get all het up about not getting a result immediately.”

Simon Rocker is a journalist with the Jewish Chronicle