The president of the United Synagogue Stephen Pack has warned that the election of Reform representative Laura Marks as the next president of the Board of Deputies could be “divisive”.

Ms Marks, who is senior vice-president of the Board, last week reversed her decision not to stand for the presidency and became the fourth candidate to enter the contest.

But in a further twist to the most closely-fought communal leadership election in years, the head of the country’s largest Orthodox body said that he was “very surprised she has changed her mind. She told me only a couple of weeks ago why she decided not to stand as president and there were several compelling reasons - both personal and communal.”

Mr Pack added that it was it was “hard to predict what would happen if she were elected. At a minimum, I think it would be very divisive and would lead to some extremely difficult conversations. At its worst I think it could result in the United Synagogue distancing itself from the Board.”

He said that he would have been “very happy” to support Ms Marks for a second term as vice-president.

Her fellow vice-presidents Alex Brummer and Jonathan Arkush, both United Synagogue members, are contesting the presidency, as is Federation member Richard Cohen.

Last autumn the JC revealed that Ms Marks, who represents the Movement for Reform Judaism at the Board, had joined Highgate United Synagogue as an associate member in order to understand the US better.

The Mitzvah Day founder said at the time that she was “passionate about bringing the community together”.

Some US members have been concerned at the increasing profile of non-Orthodox movements within the Board and a recently published strategy report into the US cited the belief among some that the Board was not best serving its interests.

Representatives of US congregations make up roughly a quarter of the Board’s deputies. But they vote as individuals, not as a religious bloc.

Mr Pack said that the next step was to arrange hustings for US deputies to quiz the presidential hopefuls. “I am interested in giving them the opportunity to see the candidates and find out what they stand for,” he said.