It is the big question that has been bothering UKIP leaders for months.
By Nick Assinder
BBC News Online political correspondent
Are they better off with Robert Kilroy-Silk inside the party or outside?
Kilroy wants to lead UKIP
The old adage that it is better to have such mavericks inside the tent spitting out than outside spitting in clearly did not apply in this case.
The former chat show host spent much of his time while on the inside spitting at those gathered around him under the party canvas.
Now he has gone - sort of. He has one leg out of the tent but the other remains inside preventing the other happy campers from zipping up the flap behind him.
And the question remains, will UKIP now suffer from losing its most instantly recognisable star (leaving Joan Collins aside)?
It is probably true to claim, as the man himself undoubtedly would, that it was his profile and "charisma" which attracted voters and big cash donors to UKIP.
He certainly gave the party's image a boost in the campaign leading up to the summer's European parliament elections where it made big gains and attracted new members.
And he had been personally promised, by an anonymous donor, as much money as the party needed to contest all marginal seats at the general election.
Kilroy angered Knapman
But UKIP's bosses had become increasingly fed up with Mr Kilroy-Silk's public attacks on them and his attempt to take over the party.
They have argued that his larger-than-life personality and occasional outbursts - such as wishing to "destroy" the European Parliament - were damaging their image.
That came to a head during the party conference when Mr Kilroy-Silk declared his aim was to kill off the Tory party.
Most to fear
And that led to one of UKIP's biggest backers, millionaire businessman Paul Sykes, withdrawing his support and switching back to the Tories.
At the same time, there has been an ongoing internal row over how the party should widen its appeal by producing policies on all areas rather than remaining a single-issue group.
And the party leader, Roger Knapman, believes UKIP's main strength lies in the fact that it strikes a chord with Eurosceptic voters who have previously had no party arguing their case.
Sykes withdrew support
Meanwhile, this was all great news for the Tory party, which had most to fear from UKIP.
Some in Conservative Party HQ are wondering, however, whether it would serve their purposes to see UKIP returning to its pre-Kilroy days.
At least with him firmly inside the party causing trouble like seeking support for a leadership coup from local parties it could only have continued to damage UKIP.
The next question, of course, is whether Mr Kilroy-Silk will now stand for a Commons seat at the general election - and if so, against who?