I have been observing the "Big Society" at close quarters this summer, establishing a small charity helping the long-term unemployed find work in the creative industries. I also spent a week visiting artists and writers in Jerusalem, where I was struck by the gulf in liberal intellectual opinion between Israel and Britain.

But the most memorable conversation I had recently was with a prominent member of the UK Jewish establishment who told me of his serious concerns about the future.

He told me that we have now come to the end of a golden period for relations between British Jewry and the government. With Tony Blair and Gordon Brown in Downing Street, Britain's support for Israel was unequivocal. Both men had a genuine understanding with the community.

The philanthropist I spoke to said that the understanding, developed over 13 years of New Labour, could no longer be guaranteed.

We have now had the best part of three months to get the measure of the new coalition and the approach of Labour in opposition. Now, at the heart of party conference season, it is possible to draw some early conclusions about the new political landscape. The outlook seems particularly stark in relation to Israel.

No political party is an ideological monolith and this is clearly even less the case in a coalition. David Cameron's comments in Turkey over the summer, about Gaza being a "prison camp", demonstrated that there has been a change in the mood music around Israel.

Foreign Secretary William Hague has been more than happy to criticise Israel in the past and has no particular passion for the Middle East. Meanwhile, the Liberal Democrat position has been consistent: Britain should be a critical friend to Israel, with the emphasis on "critical".

During the final debate of the Labour leadership contest, David Miliband chose to illustrate his independence within Tony Blair's government by emphasising his opposition to the Lebanon war.

There would seem to be serious grounds for pessimism among those who see the government's relations with the Jewish community tied to those it has with the state of Israel.

But there is another way of looking at it. There are grounds for believing that a degree of complacency crept in during the Blair-Brown years. In these new times, there is no room for such complacency. The government will need to be held to its promise of reform on universal jurisdiction in the face of possible coalition splits.

More profoundly, this may also lead British supporters of Israel, Jews and non-Jews, to reassess their own relationship with Israel. The argument for UK support of Israel will have to be reconstructed and restated. In many ways this is no bad thing, and the opportunity should be welcomed by those who believe the argument is worth making.