Sketch By Nick Assinder Political correspondent, BBC News website

The fact that "caretaker Cable" cannot remember the number of leaders the Liberal Democrats have had in recent years says it all really.

Mr Clegg is the third leader in as many years

During his welcoming speech to the new - well, latest - party boss, Mr Cable referred to the three previous leaders sitting in the audience.

"Four" came the shout from the throng of eagle eyed Lib Dems MPs, workers and hacks who had spotted David Steel sitting in the front row alongside Charles Kennedy, Paddy Ashdown and Ming Campbell.

"But that was before the merger," offered the quick-witted Mr Cable.

He was, of course, right. Lord Steel was leader of the Liberal Party before and during its unhappy alliance with the SDP which ultimately led to the creation of the Lib Dems.

Those were in the days when the party changed its name more often than it changed its leaders.

Real change

The challenge for the new man Nick Clegg is to change the change (of leader) that the Lib Dems have become fond of.

He declared: "I want today to mark the beginning of a real change in Britain. The beginning of Britain's liberal (that will have pleased Lord Steel) future.

"My election as leader today marks a new beginning. Today is about two things - ambition and change."

Mr Cable seemed to forget one former leader

The immediate problem for this youthful new leader is the need to build up his public profile - huge numbers of voters have no idea who the leader is.

There were even bystanders at the leadership event in a trendy hotel near Covent Garden who, when asked, claimed it was "that man Ming" or "the red haired one".

And that will make it difficult for Mr Clegg to get his message of change heard, particularly once the excitement of the leadership contest has passed.

To that end he has promised to hold regular town hall meetings with ordinary voters to engage in "new politics, people's politics".

Presumably these events will not be stage-managed rallies packed with Lib Dem supporters - that would defeat the purpose.

Tiny majority

The idea had a smack of Paddy Ashdown's secret away days living with ordinary families across the land during his time as leader.

Other bits had echoes of Gordon Brown - all that talk of providing change and new beginnings - while he also made it very clear he was out to win over disillusioned Tories as much as Labour voters.

But there was a niggling question mark over Mr Clegg's election victory.

He only won the contest with a majority over rival Chris Huhne of 511 votes out of more than 40,000 cast.

If there are any troublemakers left who want to make life difficult for their new leader they will undoubtedly claim he failed to win the mandate to change the party the way he wants to.

So, not only does Mr Clegg have to get his face on the nation's TV screens and newspapers, he will also have to stamp down hard on any signs of such rebellions.

For the moment, however, there appears to be a widespread feeling amongst Liberal Democrats in Westminster that the time for change of leader is over.

If that turns out to be true it will give Mr Clegg at least a decent shot at getting his and the party's message across to the country in time for the next election.