Dayan Ehrentreu was born in Frankfurt in 1932 to Rabbi Yisroel and Rebbitzen B. Ehrentreu. His paternal grandfather was the Munich Rov, the Gaon HaRav Chanoch Ehrentreu, after whom he was named. When his family emigrated to the UK, his rabbi father became principal of Prestwich Jewish Day School. Young Chanoch went to school in Letchworth, and then, after the war, to Hasmonean High School, before going on to study at Gateshead Yeshiva.
Dayan Ehrentreu was appointed to the post of Rosh Beth Din in London by Lord Jakobovits in 1984. He was known as the Rosh Beth Din (rather than the traditional "Av" Beth Din) as the title of Av Beth Din is formally held by the Chief Rabbi. By dint of his workload as well as convention of his office, the Chief Rabbi is not involved in Beth Din work. Serving together with Ehrentreu during his tenure were Dayan Kaplan, Dayan Menachem Gelley, Dayan Abraham, Dayan Binstock, and Dayan Yitzhak Berger (Consultant). Dayan Ehrentreu retired from the Beth Din in January 2008 but continues his responsibilities as a consultant to the Beth Din. became Av Beth Din of European Beth Din (Basel, Switzerland) 2008.
Ehrentreu is a leading authority in all areas of Jewish law, with particular expertise in the fields of Medical Ethics, Conversions and Kashrut.
In March 2003, Ehrentreu successfully negotiated the construction of the North-West London eruv. He has presented to the House of Lords Select Committees on medical ethical issues, such as stem cell research and euthanasia. The Chief Rabbi commented when Ehrentreu announced his retirement, "The Dayan possesses a rare combination of authority, wisdom, compassion and understanding of our community."
Dayan Ehrentreu is the rabbinical European religious authority of Tiferes Bais Yisroel, an organisation founded to reinforce halachic standards for conversion.
North West London eruv
In March 2003, after many years, Ehrentreu successfully negotiated the construction of an eruv in London. The eruv itself is an 11-mile enclosure in northwest London encompassing some of the city's Jewish neighbourhoods, including Golders Green and Hendon, plus much of Hampstead Garden Suburb and some of Finchley.
Although established with the help of Rabbi Alan Kimche, Rabbi Jeremy Conway and others, its halachic validity was strongly contested by many other prominent London Rabbis. The controversy was re-ignited in 2008, when supporters of the eruv distributed brochures to local Jewish homes, which aimed to demonstrate the eruv's halachic validity. The rabbinic opponents of the eruv were unconvinced, and reiterated their position that usage of the eruv amounts to a desecration of the sabbath.
Notwithstanding the controversy over the North West London eruv, its establishment set a precedent, with eruvs having now been established in Elstree/Borehamwood and Stanmore under the supervision of the London Beth Din and with Dayan Ehrentreu's guidance in Edgware.
Following Dayan Ehrentreu's lead, Eruvs have been planned for other Jewish communities throughout England, notably in Manchester, where the plans are supported by the leading Haredi authority, Rabbi Menachem Mendel Schneebalg of the Machzikei Hadass community. However, an attempt to construct an eruv in the Haredi community of Stamford Hill in 2008 was scuppered due to the fierce opposition of Rabbi Ephraim Padwa, the principal rabbinic authority for the UOHC, the umbrella organisation for London's Haredi community.
The Louis Jacobs controversy
Ehrentreu was involved in another controversy in the summer of 2003 when he banned Rabbi Dr. Louis Jacobs from taking part in a synagogue service on the Sabbath before his granddaughter's wedding. This led to heated debate in the Jewish community with some condemning the decision as petty and vindictive, whilst Ehrentreu and Rabbi Sir Jonathan Sacks argued that Jacobs could not appropriately say the blessing on being called up to read the Torah, because of his beliefs about its authorship.
- "Profile: Dayan Chanoch Ehrentreu"
- "House of Lords – Select Committee on Assisted Dying for the Terminally Ill Bill "
- "Beth Din head retires"
- "The NW London eruv controversy"
- "Eruv friends go on glossy PR offensive"
- "Elstree & Borehamwood Eruv"
- "Stanmore Eruv"
- "Edgware Eruv"
- "Manchester Eruv – Haskomos" Archived 15 April 2012 at the Wayback Machine.
- "Not In My Back Yard"
- "Obituary of Rabbi Jacobs in the Times"
- "Obituary of Rabbi Louis Jacobs in the Daily Telegraph"