Mick Palmer is drawn to the water. It's part of the reason why the former Australian Federal Police commissioner has hung his holster in the coastal town of Banora Point, just south of Tweed Heads, and also why he's chosen to meet me for lunch at Circular Quay, arguably Sydney’s most iconic harbourside location.

It's a warm December afternoon and we’re seated at the Sydney Cove Oyster Bar, next to the green, cast-iron railing that separates us from the waves churned up by the passing water traffic.

Former AFP commissioner turned drug reform advocate Mick Palmer. Louie Douvis

Sitting on the tourist promenade to the Opera House, the restaurant is housed in a brown-brick building, built in early Federation style, which served as a public toilet block from 1908 until its conversion into as a restaurant in the late 1980s. During this decade, Palmer frequented many cafes surrounding the Manly ferry terminal as he pondered his future as a police officer and the ideas that have come to define him.

"Sydney is a huge, bustling community but the harbour has always been a point of tranquillity," he tells me, adding he spent several New Year's Eves watching the city fireworks from North Head, where he had also done the executive police training that caused him to ruminate.

"The sea’s always been good for me, and I think for a lot of people, but in my case it really allowed me to clear my mind."

Although he retired in 2001, Palmer's resume as a former AFP commissioner and commissioner of Northern Territory police has given his stance on drugs special status in a public debate inflamed by the recent MDMA-related deaths of six music festivalgoers, at whose inquest he would end up telling his own story from the witness box earlier this year.

His observance of the futility of the otherwise "successful" smuggling seizures carried out by his former organisation set him on the path to becoming of the key advocates for the decriminalisation of possession of drugs for personal use in Australia.

I’m so eager to hear his story that ordering and eating become secondary, so I suggest we diligently scan the menu before launching too far into conversation. He says he’s a “dump truck”, as his wife puts it, and when the waiter arrives he leaves the bulk of the ordering up to me. I ask for a plate of ten Sydney Rock and Manning River oysters to start.

For mains, he chooses the Cone Bay barramundi with roasted fennel, hazelnuts, and dill vinaigrette. Seafood is a regular part of Palmer's diet, both at home and when he occasionally dines out in local restaurants.

He is the first to admit he is a "bloody hopeless fisherman", though as a younger man in the Northern Territory, he and his friends used to fish for barramundi in crocodile-infested waters, filling the boat with their catch before 7am.

Sydney Cove Oyster Bar's barramundi. Louie Douvis

I decide on the tiger prawn linguine with cherry tomatoes, basil, chilli, confit garlic, and white wine. When I pick a glass of the Journey Wines Yarra Valley pinot noir, he follows suit.

Palmer says he "didn't really" ever want to be a police officer; he was originally lured to the force in 1963 at the age of 21 by a poster of an NT ranger sitting on a car bonnet with a .303 rifle slung over his shoulder.

"I fell in love with the place," he says, adding it's where he met his wife and stayed, for the first time around, for 15 years. It was during that original stint that he had an experience that would come to epitomise what he viewed was wrong with policing.

As a detective, he and a colleague were called to a break-in at a grocery shop in the suburbs of Darwin. The owner was perplexed: the only things stolen by the two boys she'd seen running from the shop were tins of sour apple. They found the family sitting down to a tinned apple dinner in their home, with tins in the fridge and the cupboards as well. There was no other in the house.

"Mum was a gambler and dad was an alcoholic," Palmer says. "A classic case of kids stealing food to feed their bloody families."

He and his colleague recompensed the shopkeeper for the stolen goods. They took no action against the boys, rather referring the case to welfare workers.

"That's when I really started to think about the importance of distinguishing between symptoms and causes. I said, 'We've really got to spend more time focusing on some of the causes out here and making sure what we’re doing is really achieving the ends that policing is intended to achieve'."

A back injury led Palmer to quit the force and resettle in Brisbane, where he studied law and pursued a legal career in which he represented many people on minor drug charges, "and [found] that in the vast majority of cases they were decent young men and women who otherwise weren’t likely to come to the attention of police".

The tiger prawn linguini. Louie Douvis

"That made me really think and question drug policy," he says.

He returned to the police in 1983: "I thought it was the worst mistake I’d ever made, I questioned everything I'd accepted before, it drove me mad for about six months." A successful tilt at the deputy commissioner position saw him quickly launched into the role of commissioner, a position he carried over to the AFP in 1994, serving there for seven years.

During his time at the AFP, Palmer concentrated his efforts on major drug seizures and locking up traffickers, which he still believes is necessary, though he came to realise it was having little effect on end users.

"Sure, we’d taken 6000 hits off the street; the problem was nobody on the street noticed ... because when they wanted one they could still get one."

Palmer can't remember exactly when he first went public with his views about drug reform, but it was after he had retired from the force. In his post-policing career, he headed up a number of inquiries, including one into the unlawful detention of former Qantas air hostess Cornelia Rau in an immigration centre for 10 months. This "brought home the damage that can be incidentally caused by a strong government policy not subject to proper oversight and review", he said.

In 2012, he was invited to speak at the launch of a landmark report by progressive think tank Australia21 that called for a rethink on drug prohibition. As a result, he was subsequently recruited as a director of the non-profit organisation, a position he left after several years to focus on broader drug policies.

These days Palmer is most active as a spokesperson for the Take Control campaign, a movement launched by the Ted Noffs Foundation – a drug and alcohol treatment service – that pushes for pill- testing and decriminalisation of personal drug use.

It has seen him emerge as one of the main reformist commentators as the drug debate has intensified over the past 12 months.

On the day in November that Deputy State Coroner Harriet Grahame's findings into the festival deaths were officially handed down, Palmer stood side by side with Ted Noffs Foundation CEO Matt Noffs and Jennie Ross-King, whose 19-year-old daughter, Alex, died after taking almost three MDMA capsules at a festival in January, calling for the NSW government to support the recommendations. They included pill testing, a drug summit and removing sniffer dogs from music events.

More recently he challenged NSW Police Commissioner Mick Fuller over his comments in The Daily Telegraph that kids need to have a "little bit of fear" of police, describing such views as "frankly frightening".

Mick Palmer at the Oyster Bar Restaurant. Louie Douvis

Palmer says it was a difficult decision to openly criticise the messaging of another police commissioner, but "if I was going to be true to myself I couldn’t let that sit. Silence was implied acceptance".

'If I was going to be true to myself I couldn’t let that sit. Silence was implied acceptance.' Mick Palmer

But he also recognises that this debate needs to be conciliatory, which is why he and Matt Noffs plan to tour Rotary clubs around the country, taking their message of reform to "middle Australia" and the "unconverted".

It's for the same reason he believes the branding around pill-testing needs to change to something slightly more sterile, like "drug checking" or "drug warning", to reflect the interventionist nature of the procedure.

Now in his late 70s, Palmer is an animated conversationalist, projecting effortlessly above the throng of businesspeople and tourists seated around us at the restaurant. He stays largely on-message, deviating from our main topic only a few times, including to point out the attributes of the Fitbit on his right wrist and the 10,000 steps he sets out to meet every day.

Though he arrives to our meeting in a summery short-sleeved shirt with the neck unbuttoned to reveal a gold chain, Palmer is the more stately-looking figure among the cohort of reformers with which he is often grouped.

He is aware that, as a former police officer, he is qualified to talk about the failures of prohibition in ways his contemporaries aren't, which also bestows a severe obligation on him to be truthful and informed about what he says.

"You can't write me off as a bleeding-heart advocate, I started my journey on completely the opposite side of the fence; I am where I am because of what I've done," he says.

The receipt after lunch at Sydney Cove Oyster Bar. Louie Douvis

In September, retiring Queensland drug squad detective Superintendent Jon Wacker came out in support of diverting recreational drug users away from the criminal system, a position Palmer lauded as "enormously valuable" and one he said he wouldn't have had the courage to make as a serving police officer. He says he's recently spoken to a number of other senior Queensland police who share Superintendent Wacker's view.

Palmer says he was taken aback when he met Ross-King and other parents of the young revellers, all aged between 18 and 23 when they tragically died: "It personalised the problem in a way I think we really need to do."

From there he segues to discuss former NSW premier Mike Baird, who changed his mind about medicinal cannabis after meeting the family of a terminally ill cancer sufferer.

"If you give yourself the chance to listen to the reality of the evidence, the reality of the experience, see if you still come down with the same view you've got now, and I suspect you bloody wouldn’t," he says.

Given his prior vocation, Palmer is big on "evidence". In another vocal stance against a NSW leader, he recently branded Premier Gladys Berejiklian's determination that the government was now "closing the door" on pill-testing a "shocking disregard for evidence-based policy".

"I get really sour on ideology driving this, this is not about ideology. My ideology would [once] say 'hang them high', but I’ve come to realise that's nonsense," he says.