When a business has a declining revenue stream, it retrenches. Assets can be flogged, strategies can be changed. When a religion’s congregation declines, and the cashflow suffers, fewer such options are open.

The Jewish population – defined as those who identify themselves as Jewish and/or who belong to a synagogue – has fallen by a about a third since 1950 to 300,000. Balancing the synagogue books ir more difficult.

The financial picture is muddied, however, by the complex relationship between the many strands of Judaism. There is no overarching body for the running of Judaism as a religion, nor is there a single spiritual leader.

There are an estimated 341 Jewish congregations. Many, however, have declining memberships meaning that buildings are running at best half empty or, worse still, are closing.

The United Synagogue, Britain’s largest Jewish organisation, which directly owns 65 synagogues, has begun to turn the corner in terms of membership after years of decline.

The latest published accounts for the United Synagogue reveal income in 2005 of £28.6 million, a rise of nearly £4 million over the year. Membership income rose 3.4 per cent to £7.1 million, but donations fell from just over £7 million to nearly £6.2 million.

Most of the rise in income came from a £4.38 million “net gain on disposal of tangible fixed assets”, up from £335,000 of asset sales the year before. Fixed assets, which includes properties held at book value, are valued at £58 million.

The United Synagogue is still paying the price of trying to resolve what its accounts, signed off by its president Simon Hochhauser, state is “a decision to resolve the long-running pension crisis within the organisation”. It has committed an additional £3.8 million to fund the shortfall for deferred scheme members, pushing part of its reserves into a temporary negative position.

Under the leadership of its chief executive Rabbi Saul Zneimer, the United Synagogue seems to be playing a good long game in building up membership with the young. This should ensure that revenues are there to build up the wider needs of the synagogue’s community, from kosher food supervision and burials to education and care for the underprivileged.

The United Synagogue has about 30,000 household memberships, equating roughly to 100,000 individuals. The formation five years ago of Tribe, a heavily discounted youth scheme, has taken in 10,000 new members. Rabbi Zneimer says: “Many of those who joined Tribe are not members of the United Synagogue, but I am not trying to point score off others.”

Judaism splits broadly along two lines of religious practice and synagogue membership between the Orthodox and nonorthodox. Lining up for Orthodox in the UK are the Spanish and Portuguese Jewish Congregation of England, the United Synagogue – founded in 1870 – and the Federation of Synagogues. Representing the nonorthodox are the Movement for Reform Judaism, Liberal Judaism and the Assembly of Masorti Synagogues. Reform Judaism was the first breakaway nonorthodox movement originating in mid-19th century Germany.

Rabbi Jonathan Sachs, the Chief Rabbi, therefore bears a somewhat misleading title as he is spiritual head of the United Synagogue, but not in charge of either other Orthodox groupings or any of the nonorthodox.

The oldest community is the 351-year-old Spanish and Portuguese Jewish Congregation for England headed by Rabbi Dr Abraham Levy. He is the spiritual head of its eight synagogues. As its name suggests, the community hailed originally from the Iberian peninsula.

A subgroup called the Spanish and Portuguese Congregation of London (the first congregation in Britain) owns three of those eight synagogues: the City’s Bevis Marks, the country’s oldest and open since 1701; Lauderdale Road in Maida Vale; and Wembley.

Howard Miller, chief executive of the Spanish and Portuguese Congregation of London, reckons on an annual income of about £1 million for its three synagogues. About 40 per cent of income comes from synagogue membership fees. A typical family annual fee for Lauderdale Road is £600 which, like other synagogues, includes Sunday religion school.

Another 40 per cent of income derives from a £6 million investment fund, set up years ago by member donations and now run by outside specialists. “It is primarily in equities and relatively low in direct property.” He has not put a value on the properties as there is no desire to sell.

There are another 15 congregations loosely known as the Sephardi (the modern Hebrew for Spain) orientals, all autonomous but working closely with the Spanish and Portuguese.

The Federation of Synagogues was founded in 1887. The movement today has 13 centrally owned synagogues and 11 affiliated members that are self-financed. All the synagogues look to Dayan (meaning judge) Yaakov Lichtenstein as their spiritual head. The hunt for a chief executive is under way.

“The Federation is a wealthy organisation as they own their own property. I look after the religious side,” says Dayan Lichtenstein. Affiliated synagogues in Tottenham and Hackney closed recently, reflecting the decline of local Jewish populations, while Elstree has just opened. “It’s a boom area. We are in a state of flux,” he adds.