The biggest test for Chief Rabbi Ephraim Mirvis was always going to be the role of women in synagogue life. It was only a matter of time before egalitarian trends within American modern Orthodoxy reached the UK.
Although the four or five partnership minyanim (PMs) which meet every few weeks in different parts of London may attract only a small minority of United Synagogue members, they have begun to make their presence felt.
The Chief Rabbi has previously ruled that PMs - where women can lead some prayers and leyn from the Sefer Torah - are out of bounds for the US. But now he is faced with a potentially tricky decision of what to do about those involved in them.
Some rabbis have simply ignored PMs on their patch and taken no action against anyone associated with them. Although his office this week says simply going to a PM itself should not prevent a person from playing a "full and active part in our synagogues", that still leaves some wiggle-room for local rabbis to decide what to do.
While the Chief Rabbi has declared his support for Borehamwood, but since that shul's leadership has not clarified its policy, we will have wait to see what that means in practice.
The US has long prided itself on its traditionalist understanding of Orthodoxy while welcoming Jews of any level of observance within its ranks. The role of women has become a touchstone issue.
The US does not want its Orthodoxy questioned by the expanding Charedi right. At the same time, to the left, there are increasing numbers of Orthodox feminists who remain deeply dissatisfied with the status quo.
There has been some movement under Rabbi Mirvis. There are now women-only readings of the Book of Ruth on Shavuot in some of his communities, besides the longer established practice of women reading the Book of Esther. But when women at Borehamwood wanted to read from a Sefer Torah for Simchat Torah in a women-only group two years ago, the Chief Rabbi said no.
The central Orthodox authorities have been distinctly wary of one of the bidders for a new Jewish free school, Barkai College. Even though Barkai's leaders have made clear they have no plans to introduce PM services for pupils, their wish to have girls leyn from the Torah in women-only services was radical enough.
A year ago Rabbi Mirvis issued a warning to his rabbinate to avoid "inappropriate speakers". He did not give details, but it was widely seen as a response to Hampstead Synagogue's appointment of Dina Brawer as scholar in residence. Mrs Brawer is currently studying at an American Orthodox yeshivah which ordains women. It remains to be seen whether she will be welcome to speak in US shuls and schools when she returns.