The Reform movement’s leadership succession plans have been derailed by the decision of Rabbi Shoshaha Boyd Gelfand, the designated chief executive, to leave for a new job outside the organisation.

Rabbi Boyd Gelfand, the current executive director, was due to take over the professional reins of the organisation from Rabbi Tony Bayfield, who retires as head of movement at the end of the year.

But she has instead chosen to become the new director of JHub, the centre for Jewish social action enterprise and innovation.

She will, however, be the first female professional rabbinic leader of a UK synagogal body for a few months – she will remain at the Reform movement till the middle of next year until her successor is in place.

A new post of director of operations and support is also being advertised ahead of the forthcoming retirement next spring of Mike Frankl, the director of finance and synagogue services. Debbie Reeves has been promoted internally to finance director.

The succession to Rabbi Bayfield – who will become president of the movement – had been planned well in advance. He had brought forward his handover to Rabbi Boyd Gelfand after originally planning to step down next summer.

Movement chairman Stephen Moss said: “We will be sad to see Shoshana go, but are delighted that she leaves us in such good shape. I’m pleased that Shoshana and Mike will be continuing to work with myself and the board to oversee the implementation of the new structure in the coming months.”

JHub, which is sponsored by the Pears Foundation, is widely credited for fostering a new generation of Jewish activisits. Among the organisations based at its West Hampstead headquarters in London are Mitzvah Day and Tzedek.

Rabbi Boyd Gelfand will replace Lisa Capelouto, who is moving abroad.