Delicate negotations are continuing over the Board of Deputies' 250th anniversary in order to find a way to mark it to satisfy both Orthodox and non-Orthodox requirements.

Originally, the celebrations had been expected to begin with a commemorative service, on Sunday June 20, at Bevis Marks, the country's oldest synagogue, where the Board was founded in 1760.

Instead, in order to sidestep religious differences, the opening event will not be a service, but a special plenary session of the Board addressed by the lay leaders of different movements.

However, Sephardi spiritual head Rabbi Abraham Levy - who is one of the two official rabbinical authorities of the Board, together with the Chief Rabbi - still remains hopeful that a service may take place at the synagogue to conclude the 250th celebrations later in the year.

The difficulty with a service is agreeing a format that reconciles the Orthodox objection to non-Orthodox rabbis leading prayers, with the non-Orthodox wish to participate in some way.

Is it right for the Board to hold a service?

At a communal service at Bevis Marks four years ago to commemorate British Jewry's 350th anniversary, prayers were led solely by Sephardi rabbis from the host congregation. But other streams of Judaism were recognised by having the Ark opened and closed - but by their lay leaders.

Rabbi Levy said he had proposed a similar service at the historic synagogue to coincide with the honouring of the next Lord Mayor of London, who is expected to be Jewish. "I have heard nothing to the contrary officially," he said this week. "That is how I left it and that's how I am planning it."

Stephen Moss, chairman of the Reform Movement, said: "The details of participation in that service are still under discussion."

For the Liberal movement, its chairman Lucian Hudson said: "The community has looked at the celebration as an opportunity for cross-communal participation. That has been the spirit driving discussions - but we need to take a few practical steps to make it a reality. We're looking at the proposed options very closely."

Michael Gluckman, Masorti's chief executive, commented: "We are a pluralist community. The Board represents that, so the final service should reflect that."

But one senior Progressive figure, who did not wish to be named, believed that the final event would not be a service, so that rabbis from across the religious spectrum could take part.

Vivian Wineman, president of the Board, said: "There are various arguments against having a service: whether it is appropriate for the Board, which is not a religious organisation, to be holding services. On the other hand, we are a faith community and work very well with the religious groups.

"Hopefully, there will be a high-profile event in the City to close the celebrations."