Her first target will be Labour's record on reducing inequalities in health provision and moving funds into "Cinderella" areas such as the care of the elderly and the mentally ill.
As chief executive of the fund, Rabbi Neuberger wants to give the 240- strong institute more "focus" and by that she means commissioning research into areas where Mrs Jowell's record is most vulnerable - public health and the tension between council social services and the NHS. Any backsliding by Labour onpromises to do something about the costs of care for the very old is likely to be severely criticised.
Under Tory pressure the King's Fund backtracked on its radical proposals for closing St Bartholomew's Hospital in order to put more money into local health services in Hackney and other poor districts. Under Labour, such plans could be revived - pitting the Fund against ministers who have promised to sustain Bart's and the other inner-London teaching hospitals.
Temperamentally and politically the two women have a lot in common - including ambition to make their mark.
Rabbi Neuberger, 47, is the mother of two teenage children. She is centre- left, while Mrs Jowell, despite evidence of some radicalism as a Labour councillor in Camden in the Seventies, is one of nature's Blairites. Her closeness to the Prime Minister has, paradoxically, been reinforced by the recent disclosure of the involvement of both her husband, David Mills, and Mr Blair with racing industry interests. Last week Mrs Jowell carried the can for Labour's decision to exempt Formula One from the tobacco sponsorship ban.
Rabbi Neuberger's determination to commit herself to the King's Fund is shown by her decision to resign from appointments to 47 voluntary organ- isations and quangos. (She does not promise, however, to stay clear of Jewish controversies, especially if provoked by the Chief Rabbi, Jonathan Sacks, to whom the idea of female rabbis is anathema.)
The King's Fund, launched at the end of the 19th century by the Prince of Wales (later Edward VII), is politically neutral. But Rabbi Neuberger will be seeking to raise its profile. Subjecting the Government to sharp appraisal is going to be the best way of keeping in the public eye.
She will, she says, lay off Labour's spending record. She belongs to the school of thought which says the NHS's problems with money are endemic but as long as resources increase by a small amount in real terms each year, it can manage.
Instead, what she wants to see Labour doing is the hardest thing of all - redistributing money from one health service to another, from one area to another, and from one social group to another. "My priorities, personally, are the socially excluded," she says. "In parts of the country, including London, the elderly are accused of 'bed blocking'. In fact, it is harder for them to get hospital treatment."
Mrs Jowell is unlikely to welcome the rabbi's vow that the King's Fund is going to be an active player in discussion of health issues in London, especially as debate is certain to heat up as residents of the capital move towards voting for a mayor.