"Just heard a rumour that Charles Kennedy will defect to Labour as soon as they find the WMDs in Iraq". So tweeted Liberal Democrat councillor Nick Barlow over the weekend, summarising one of the reasons why the story of Charles Kennedy's defection to Labour never seemed credible.

But while the story itself is, as Kennedy himself put it, "the silliest of silly season stories", there is no doubt the Liberal Democrats are in unchartered waters. Nick Clegg has given the party something members never expected to happen any time soon: power.

It is a double-edged sword. On the up side, it is no longer a matter of the Liberal Democrats making 101 proposals in Parliament and hoping that, one day, one of the other parties would take one up and claim it as their own. On the down side, as we did not win the election ourselves, we are in a government with many members from another party and many of whose policies are not our own.

I have been around almost a third of the Liberal Democrat local parties in London over the last few weeks, talking at events, helping at by-elections and so on, and there has been a common pattern of people's comments. Concern over some of the Conservative policies the coalition is implementing; leavened by delight at seeing progress on the particular Liberal Democrat concerns dear to their heart, such as the environment, civil liberties, Pupil Premium or political reform.

As a result, my thesaurus is now well-worn at the page containing the word "pensive", which is perhaps the best one-word summary of the mood. The non-Liberal Democrat policies the coalition is implementing are a mixed bag. Some are better than were the party's own policies. Some clearly are not ones a Liberal Democrat government would ever consider. That is the reality of coalition government.

Where the balance may go wrong is if members feel the party concedes too much in policy negotiations to stay in power.

In the Seventies, the then Liberal MP John Pardoe wrote: "Without political power, Liberal principles and policies will remain in the wings... [but] we must never clutch the cloak of establishment too close around us."

There is much wisdom in those words. In the meantime, plenty of those principles are finally being implemented by the Government.

The writer is co-editor of the website Liberal Democrat Voice ( www.LibDemVoice.org)