The siege ended in casualties and gunfire at the Lindt Cafe at Martin Place Picture: News Corp/Bill Hearne Source: News Corp Australia

And, possibly, a conversation with the Prime Minister.

These might have been easier to grant than a million unmarked dollars and a helicopter to freedom, but NSW police negotiators would have rated them as very sinister requests indeed.

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Take up arms ... Police at the Siege at the Lindt cafe which saw the gunman and two hostages killed. Picture: Richard Dobson Source: News Corp Australia

Queensland barrister Patrick Van Grinsven, who spent 21 years with the police and 12 years of them as a counter-terrorism-qualified specialist negotiator, said police would have been concerned it was providing him with the tools for a horror show.

“If he got the ISIS flag, he could use that to make a very dramatic statement indeed,” said Mr Van Grinsven, who has trained closely with the NSW negotiators on the scene at Martin Place.

A request to talk to the Prime Minister would also be ruled out.

“That’s a difficult thing to concede to,” he said. “It sets a dangerous precedent. Governments around the world would not consider that.”

Negotiators would be concerned that if they put Tony Abbott on the line, Monis could ratchet up his notoriety even further by using the moment to execute a hostage, an unacceptable risk for all.

Police knew this had happened in domestic sieges. “They say, I just wanted to speak to mum and dad, and then they can make very dramatic statements such as killing themselves or killing someone,” said Mr Van Grinsven.

At the ready ... Police take up position while the siege was underway. Picture: Reuters/David Gray Source: Picture Media

As for the media broadcasting his supposed request that Australia was under attack by ISIS, the police requested they not relay his demand for the same reason.

“This person may have been trying to set up an international stage,” said Mr Van Grinsven.

“It could be as serious as trying to do a live execution. We have seen others prepared to do that. This goes through negotiators’ minds.”

The idea that authorities will refuse to negotiate with hostage-takers is a myth.

Establishing contact and a rapport in order to build towards negotiation is essential — as shown by Israeli negotiators, who have succeeded in saving lives by talking suicide bombers into removing their vests.

More to it ... Queensland barrister Patrick Van Grinsven said while Monis’s requests seemed simple NSW police would have rated them as very sinister indeed. Picture: Craig Greenhill Source: News Corp Australia

But keeping someone on the line is a very different proposition to caving in to terror.

Negotiators took several long hours to make contact with Monis. Initially, it appeared he wanted to stage the siege via direct arrangement with the media, which was not granted.

But once they got him on the line, they needed to play him carefully. “If someone asks for something outrageous, you don’t give a flat ‘no’,” said Mr Van Grinsven.

“That’s confrontational. You can heighten tension.

“There’s some things the authorities will concede and others they won’t. The skill is to make the person come to the realisation that what they’re requesting is not feasible or obtainable.”

The type of things that could be obtained depend on the situation: sometimes providing food and water could be the most important thing, though not in this case.

Trying to resolve ... NSW Police Commissioner Andrew Scipione confirmed during the siege that police negotiators had made contact with the gunman. Picture: Mark Metcalfe/Getty Images Source: Getty Images

“The art of negotiation is for you to try and get something for something, maybe a simple assurance that no one is harmed. That’s how you start to build the relationship of trust.”

In this case, it is believed Monis got nothing that he asked for; and it is not clear how far the negotiators were able to develop the relationship with him.

However, they would have been mindful that as the night dragged on, this lone wolf would have needed sleep. They could not risk making him irritable because it would have made him more dangerous.

And they may have been hoping that sleep would provide assault police with their best chance.

Psychologists consider there are six main types of hostage-taker: the emotionally disturbed, political extremists, religious fanatics, criminals or prisoner inmates — and Monis could qualify for almost all of the above.

First rule ... Patrick Van Grinsven, said establishing contact and a rapport in order to build towards negotiation is essential. Picture: Supplied. Source: Supplied

According to British forensic psychologist Amy Grubb, the foundation of modern negotiation techniques were formed after the 1972 Munich Olympics, when Palestinian terrorists raided the village and seized Israeli athletes.

Eleven hostages, 10 terrorists and one policeman died. “The incident was dealt with via force,” wrote Ms Grubb. “This tragedy highlighted the distinct lack of protocol or procedure to deal with crisis situations in a controlled way.”

It is clear that the NSW police were prepared to control the situation as best they could to minimise hostage casualty.

But the situation became dynamic and it triggered a response. The talking was over.