As head of Brisbane's G20 security operation - repeatedly billed as the largest peacetime security event in the nation's history - the Queensland Police Assistant Commissioner was charged with the task of keeping the meeting of 26 world leaders violence-free.

Yet, while leading the team at the control centre at police headquarters for up to 14 hours each day in the fortnight leading up to the event, the mum-of-two had arguably an equally important job to do.

"I have a 10 and 12-year-old who literally in those last few weeks didn't see me, though I was still organising their Futsal mind you while I was sitting in the policing operations centre, texting the team," she laughed.

It's that unassuming attitude that, one month on from Operation Southern Cross, is being widely credited with making the event the enormous success for which it has been hailed.

From the moment she was charged with the task of heading the security operation two years ago Ms Carroll had one distinct mantra that, in the end, meant the world leaders meeting was not marred by violent scenes of protest that detracted from previous meetigns in Toronto, London and Pittsburgh.

"Communicate, communicate, communicate. Then communicate, communicate, communicate," she said.

From day one, open lines of communication with all key groups was a key component of Ms Carroll's approach and her accessibility, along with that of Deputy Commissioner Ross Barnett, won the pair many fans along the way.

Though the debrief is far from over, it's with a well deserved smile she can now sit and reflect on its success.

"The balance was spot on," she said.

"The key to success was early, early engagement of protest groups, getting to know the people who were planning the protests, developing trust, having that dialogue and conversation."

Equally important, she said, was that the message filtered through to the troops at ground level.

"We had to make sure all police officers on the front line shared our view and philosophy as to how this would be carried out," she said.

"Our training was that it is a fundamental right to protest and that was reaffirmed in everything we did.

"Three to four weeks out, intensive negotiations commenced between expert police negotiators and the protest groups, who treated the negotiators very, very well.

"I think a relationship formed and there was a respect for each other's rights and roles."

While some critics have pointed out that extreme heat and Australia's remote location may have dissuaded protesters from recreating the violent scenes seen at previous events, Ms Carroll remains adamant the success was all in two years of intensive planning.

"The last finance minister's meeting of the G20 in Melbourne in 2006 was the only G20 meeting ever held in Australia and it was particularly violent, so we do have violent protests in Australia," she said.

"In the past even Queensland hasn't enjoyed a good relationship with protest groups in terms of past policing.

"We researched best practice around the world and we made sure it was going to better than anything we had done in the past."

While the terror threat for the G20 rose from low to medium in the lead-up to the event in response to worldwide conditions, Ms Carroll said engagement with the wealth of associated agencies, such as the Australian Federal Police and the Department of Foreign Affairs and Trade, meant she was confident the risk of any potential terrorist plot would be foiled.

"I've had to plan not only to the knowns, I also had to plan for the unknowns and when you have 26 world leaders running their countries in one place at one time, it has got to be a safe and secure event," she said.

"But with all the other agencies assisting us, the many, many layers of security, and being comfortable that those layers were comprehensive and tight, it would have to have been something so unusual to affect the safety of the event.

"We had an enviable situation in that we had two years...we studied the world to make sure we covered every contingency."

That was not to say, however, that it eliminated stress in the lead-up to the event.

"Two to three weeks out I was getting up at two...three...four o'clock in the morning and couldn't sleep again," she said.

"It was not just me, my deputy (Mr Barnett) was getting up and walking his dog around the suburbs at three or four in the morning.

"It was all of us. You own it..you have such a responsibility. It's your patch and, while you think you have got it all covered, logistically there were challenges."

Security aside, logistically Ms Carroll's team also had to co-ordinate the movement of 6500 police officers in the city.

There were 8000 flights in and out to arrange, 4400 interstate police to accommodate, 120,000 meals eaten, 20,000 bottles of water drank and 16,0000 snacks consumed among the police contingent alone.

Yet it was the main event, the safety of the world leaders, that heightened the stress of the job among the entire team of 140 overseers.

"You just hope for the best and...that day when the last world leader left on a flight at 1pm on the Monday, the cheers that went up in police operations centre were phenomenal," she said.

"We still had a lot of work to do, we still had to send out 4500 police on the Monday and Tuesday so we still had a lot of logistical work to do, but I was so happy when that last plane left.

"I loved having the leaders in town but it was good to see the last one out of here.

"That meant we had delivered a successful operation, the pressure was off, we had done it."

Ms Carroll has now been inundated with requests to consult on security matters interstate and in 2015, will address a counter-terrorism conference in the United States.

The lessons learned from the success of the G20 event will also be applied to the Gold Coast Commonwealth Games, as attention now turns to Queensland's next large-scale security event.

But it's an operation Ms Carroll has no ambition to head.

"I just think someone else should have a go at the Commonwealth Games. They need to enjoy it just like I did for the G20," she said.

After an all-consuming two years, the Assistant Commissioner is now re-adjusting to a slower pace.

"The first day I took off was the Thursday or Friday (after G20) and I was completely lost, because this had consumed our lives for so long, leading into it," she said.

"I don't think we had a break for several months. There were so many media. We were always reacting to something. There wouldn't have been a day for several months I wasn't G20-ing.

"And then to come to the Thursday I was driving around in the car and I phoned my husband and said, 'I don't know what to do with myself' because it was all of a sudden just so quiet."

In addition, the tight-knit team she led throughout that time is slowly dispersing.

"It's a sense of a family breaking up. It's not even an everyday work situation. It's an extraordinarily tight, stressful, tense situation but we have an extraordinary amount of pride and ownership," she said.

"We all wanted to get to the finish line and we all wanted to have such a successful event. To be a part of that is just so rare and its never going to happen in my lifetime again. It's hard to explain the people you meet on the way, but the experience you have is phenomenal."

As for Ms Carroll's future beyond the final wrap-up of the operation in early 2015, that will be determined by Police Commissioner Ian Stewart.

She will take her first real break in two years over Christmas, after spending two years never taking more than a week of leave at a time due to the pace of Operation Southern Cross.

She hopes to remain in the Brisbane region  - and perhaps continue the all-important job of arranging Futsal matches.

But from the sidelines, not the police command centre.