Councillor Bill Armstrong is defending himself less than a day after being taken to task by Ward 4 Councillor Jesse Helmer.

And the rebuke has council watchers wondering if the new crew could follow the pattern of infighting that dogged their predecessors.

Armstrong told CTV News Tuesday he didn't know about the rule requiring him to notify the mayor before leaving a council meeting early, but adds Helmer went too far by publicly insisting he be punished for leaving.

"My behaviour won't change because my behaviour has been appropriate and the reasons I leave are always appropriate reasons," he says.

Armstrong says he left the five-hour meeting Tuesday night just 15 minutes early for an important family commitment - after the crucial issues had been dealt with.

But shortly after he left, Helmer insisted on a vote to ban Armstrong from returning to the meeting - a symbolic gesture - because he had violated council rules by not informing the mayor of his departure.

The motion was defeated by a narrow 7-6 margin, which did reveal Helmer wasn't alone in his concern.

"Certainly in the past when it's happened I've let it slide, but here it is again, and it's just when you leave and aren't going to come back," Helmer said.

Still, Armstrong says he signed out of the computerized voting system, which would have notified the city clerk he'd left.

"In my mind it's a bit schoolish to be bringing up issues like this, we have more important things to do," he says.

Gord Hume, a municipal affairs author and former city controller, says he hopes Tuesday night's vote doesn't signal a change in what has been a relatively harmonious eight months.

"If this is the start of a different approach and attitude by this council then I think that's a matter of concern for the community cause we've had that and it doesn't work...There is a meanness in politics in Canada today that is really quite extraordinary and I would really hate to see that happening at London city council."

Armstrong would have liked to see more discretion, "[Helmer] should approach me, as he should have in the first place, if he has concerns about anything I'm doing. I'm only responsible to one group of people, those who elected me."

But Helmer says, "Obviously when someone leaves council and doesn't come back, there's not much of an opportunity to talk to them about leaving."