Tucked away in a courtyard in the City of London, surrounded by glass, steel and concrete skyscrapers, is a historic and religious gem: the oldest synagogue in the UK. On Friday evenings, at the start of the Jewish sabbath, it takes 45 minutes to light up to 240 candles in the original chandeliers hanging from the ceiling of the 320-year-old building. As well as holding prayer services, each week the Bevis Marks synagogue welcomes visitors and school trips, and hosts lectures and community events in its Grade I-listed building. Weddings and religious festivals are celebrated in the courtyard. But all this is now at risk, according to Rabbi Shalom Morris, owing to plans to build two enormous towers that will block natural light from reaching the synagogue. “We will be a mushroom in the forest,” Morris said. The proposals, for an office block of 48 floors and another of 21, are due to be decided on by the City of London Corporation next month. About 1,500 letters of objection have been sent from heritage organisations, academics and multi-faith groups, raising concerns about the impact on the only non-Christian house of worship in the City of London. The synagogue was built in 1701, the first to be constructed after Jews – banished from England in 1290 – were allowed back by Oliver Cromwell in the mid-17th century. Now it is the only synagogue in Europe, and possibly the world, that has held continuous worship throughout its existence. Originally, the synagogue was surrounded by buildings of a similar or lesser height, allowing light to stream in through arched windows. But over time, adjacent buildings have grown ever taller. A 56-storey skyscraper nicknamed the Diamond was approved in 2018. The synagogue is also worried about the potential risks of deep drilling in the area for the pile foundations needed for tall buildings, and increased noise levels from construction and from greater footfall after the towers’ completion. “I understand the City needs to grow and develop, and we have tried to be tolerant of that. But now we have reached a tipping point where this growth is endangering the synagogue,” said Morris. “We feel the sensitivity and the importance of the site have been disregarded. If this was being proposed next to St Paul’s, these towers would never be built. Bevis Marks is the cathedral synagogue of British Jewry. The planning authority views us as a nuisance rather than a treasure to be protected. The level of anxiety and frustration this is causing to our community is very difficult.” Sir Michael Bear, a former lord mayor of London, said he was an “ardent supporter” of increasing modern office space in the City, but he was “bewildered and perplexed at the way that the genuine considerations of heritage” had been treated. Historic England, the body that protects the UK’s built heritage, has also raised concerns about the proposals. A spokesperson said: “Accessed via a secluded courtyard, the deliberately enclosed surroundings are an important part of [the synagogue’s] setting and contribute to its significance. Whilst a strong sense of this survives, the courtyard has been encroached upon by recent tall building developments in the area, which has both eroded the private, intimate character it once enjoyed, as well as its prominence within its immediate surroundings.” The quality of natural light was “an important part of the character and ambience of the building’s interior”, the spokesperson added. Bevis Marks, whose congregation includes local residents, City workers, students and international visitors, has recently undergone a £7m renovation project, including the creation of a new visitor centre, completed in time for the Jewish new year next week and the synagogue’s 320th anniversary this Saturday. “This is a historical place but also a living place, a community. We’re not interested in just being a museum,” Morris said. A spokesperson for the City of London Corporation said its planning committee considered “relevant representations both for and against a development before taking a final decision” but it could not comment on specific applications.