The passionate environmentalist Neville Sassienie, who has died aged 91, spent decades promoting green issues among community leaders.

But he was outstanding for his deeply spiritual approach, in which he devoted much of his long life pondering the question of where religion stands on the issues of climate change and global warming.

Sassienie, former chair of the Movement for Reform Judaism, founded the Environmental and Social Issues Action Group at the Board of Deputies, and was considered by community leaders to be a “prophetic voice of environmentalism”.

A co-founder of Finchley Reform Synagogue (FRS) in 1974, Sassienie’s ideas for saving the planet were rooted in man’s approach to God, which inspired him to help launch Faith for the Climate, a space for faith communities working on climate change, and Eco Synagogue.

He was recently filmed discussing his beliefs on YouTube with Rabbi Jeffrey Newman of FRS, a climate activist himself who was arrested at a London Extinction Rebellion demo in 2019. Sassienie was describing the powerful impact of trips to Killin, Scotland, organised by Rabbi Newman. There he was introduced to Subud, a spiritual movement that originated in Indonesia.

Subud’s spiritual practice is the Latihan, a form of active meditation. Sassienie told Newman that despite the work of some fantastic rabbis — “my conclusion is that our religion is still in a sort of bad primary school stage… but now FRS has moved on, there is an improvement”.

Over time Sassienie developed his belief that spiritual work can be linked to political activism. He essentially held three roles; as a Jewish community leader, an environmental activist and a spiritual seeker.

Born in Cricklewood, north London, he discussed with Newman the positive effects early life problems can have on a person.

He was speaking from personal experience: his mother Rachel Proops had died when he was five and he was brought up by relatives during the time she spent in hospital.

However, he developed a close bond with his father Sam, an accountant, and after being evacuated to Cornwall during the war, spent the 1940s in Haileybury College in Hertfordshire where he became head boy in 1949, one of very few Jewish head boys at the school, he suggested later.

Neville Sassienie credit Finchley Reform Synagogue (8)

Sassienie shortly after joining Finchley Reform Synagogue (Photo: Finchley Reform Synagogue)

Responding to the Haileybury Society’s recent request for old boys’ stories, he recalled an early meeting with the Master (CPC Smith) to sound him out over the role. “I asked whether my faith was a problem. He said, a little to my surprise, that he saw no reason why it should.”

At school he loved sport. A keen rugby player, he did not allow his Jewishness to prevent him from reading the lesson in chapel, which initially opened his mind to the question of truth in religion.

He began his life-long association with the Reform movement, and became president of its youth movement. He entered his father’s accountancy firm, Barnes Roffe, but tragedy struck again when his father died suddenly when he was 22. He spent his entire career in that firm, eventually becoming senior partner. He married Margaret Cohen in 1958.

His early interest in progressive Judaism drew him into active involvement in the Movement for Reform Judaism (formerly the Reform Synagogues of Great Britain) in the 1960s and he eventually co-founded Finchley Reform Synagogue in London. He chaired the national movement from 1996 to 1999.

At FRS, which he described as one of the Progressive movement’s most creative synagogues, he joined a campaign with UK Citizens, (a community organising movement) seeking action on air pollution in Barnet.

He also became involved at the Board of Deputies in a development of Eco-Synagogue, a Jewish spin-off from the successful Eco-Church movement. This inspired him to work with the interfaith group “Faith for the Climate” led by Canon Giles Goddard from his church in Waterloo, central London.

Sassienie became particularly interested in social action both at the synagogue and at the Board of Deputies, where he launched the Deputies’ social action group with an emphasis on the challenge of global warming — “which I believe, with so many world leaders, is the greatest threat to the future life on our beautiful planet”.

Ideas of personal development ran in tandem with his spiritual instincts and he became involved in neurolinguistic programming and the Landmark Forum, an organisation offering training in personal and professional growth.

Some of his convictions were triggered by his contact in 1974 with Subud, which led to his belief in the intrinsic links between personal spirituality and collective, social and environmental transformation.

Inspired by the late journalist and broadcaster Rabbi Lionel Blue, who found spirituality in the real world, Sassienie developed a close working relationship with his synagogue’s rabbi, Jeffrey Newman, to whom he described God as a divine energy which was accessible to individuals or groups, and could spark internal change.

Rabbi Newman, himself, noted Sassienie’s positive way with his own children when they were as young as eight or nine. “There was a holiness, a very everyday down-to-earth holiness, about you, which was something I would like to learn about,” he told him.

As Howard Cooper wrote in The Guardian: “He was insistent, when talking to me, a friend and rabbi, that liturgical creativity was vital in helping Jews develop their own relationship with God and that spiritual work and political activism were indivisible.”

But at first Sassienie faced a tough battle attempting to make the Jewish community aware of the need to take environmental issues and climate change seriously as a moral imperative.

It was the 2007 launch of the Big Green Jewish Website, in which he was joined by David Miliband, former Secretary of State for the Environment, that helped persuade the community to take the environmental challenge seriously.

Neville Sassienie is survived by Margaret and their daughters Jo, Jane and Gill, and grandchildren, Ellie and Jess.

Neville Sassienie: born July, 1931. Died June, 2023