What did Nick know?

Twenty years ago, the alleged activities of former Lib Dem Chief Executive Lord Rennard would have been a matter of political gossip, and little else.

But a lot has changed since then, chiefly the party's rise from near-irrelevance to coalition government.

And that's why claims linking Lord Rennard to "inappropriate behaviour" with a number of women are such a problem for Nick Clegg.

One woman says she was told "the guy who is the problem is at the top of the tree." Another explained how she complained, only to be told nothing could be done, as no-one would make a complaint.

Channel 4 News says it first approached senior Lib Dems about the story more than two weeks before it broadcast a lengthy, detailed report.

The programme says precise allegations were given to the party more than two days in advance.

The Lib Dems issued a statement to Channel 4 News one minute before the programme was due to go on air.

We can only imagine the conversations within the party since then, but a more detailed response from Nick Clegg only emerged after the Mail on Sunday reported claims of a facebook conversation suggesting he was aware of the issue four years ago.

The Deputy Prime Minister subsequently said his office was told of "indirect and non-specific" concerns in 2008.

Lord Rennard resigned as Lib Dem Chief Executive the following year, at at the 2009 conference was praised for his "guidance and encouragement" - by Nick Clegg.

Now a Lib Dem investigation will look at whether the health grounds cited at the time were the sole reason for the resignation.

Lord Rennard denies any inappropriate conduct, and Mr Clegg says his resignation limited the opportunities to take action.

But if Nick Clegg was aware of "indirect and non-specific" concerns, why did he not enquire further? If the concerns were so indirect, why was Lord Rennard confronted with them, and warned about his behaviour? Did the party make formal contact with any of the complainants?

Had this happened in any other institution, or political party, Mr Clegg would be asking the same questions.

His statement ends with a warning that he will not allow the Lib Dems to "be subject to a show trial of innuendo, half-truths and slurs."

It's a combative end, and one that could come back to haunt the Deputy Prime Minister if there are further revelations in the coming days.