Dover: Increasingly impatient, a retired AFL premiership player sits in a humble though magnificently located caravan park on the cliff tops of Dover, England, steadily demolishing bags of chocolates.

From the window of his temporary lounge room he sees a breathtaking expanse of water. His eyes hone in on a 34-kilometre stretch with a bookend of Calais, France.

Eighteen months ago, Campbell Brown had not clocked more than 2200 metres in a single open water splash. But he is on the verge of attempting to swim across the English Channel.

Hyporthermia, loss of consciousness and sheer exhaustion are reasons most who attempt this iconic feat do not succeed. Cruel tidal and weather conditions are other dream extinguishers.

Brown plainly rejects the notion of these common stumbling blocks stopping him. Abandoning the pursuit is not an option. He says he would have to be hauled from the water. The conviction is impressive, the imagery slightly unnerving.

Achieved 1287 times by solo swimmers at last official count (more people have climbed Mt Everest), this venture for 31-year-old former Hawthorn and Gold Coast player Brown comes after he has spent an insane number of hours in frigid, salty water.

Brown's extreme dedication to swimming has been matched by extreme dedication to eating. Insulation can make or break a long distance open water swimmer. When Brown last played elite footy, he weighed 85 kilograms. He's added almost 10.

While he has repeatedly joked in the countdown to his Channel swim about his obvious bloating, Brown is discernibly peeved that he couldn't reach a target triple figure weight, despite his daily gorging.

Thankfully, the temperature of the water in Dover has risen to about 15.5 degrees. That's almost six degrees warmer than Melbourne's Port Phillip Bay right now; the place where Brown has spent hundreds of hours preparing for this expedition.

Privately, Brown harboured the ambition to swim the Channel for years, and even thought it was achievable while he was still playing footy.

When he first shared the aim, in late December 2013, he was laughed at. It wasa life-changing period for Brown. In just a few weeks he had married but he was also the chief protagonist in a messy and highly publicised controversy that finished him as an AFL footballer. This rendered him unemployed a year before he had counted on it, and to say this was an unfortunate end to a 205-game career is an understatement.

The fact Brown fractured a teammate's jaw with a punch during an end-of-season trip meant his reputation was damaged significantly. Initial misreporting that Steven May had been king hit by his older teammate, combined with what Brown saw as Gold Coast tardiness to clarify the facts, made things worse.

It was a matter of days after he and the club agreed it was best they split that Brown announced, at a special family dinner, his intention to swim the English Channel. Quizzed bout this seemingly significant confluence, Brown responds: "I'm just a very goal-orientated person."

Could he expand?

"Well, I just think it's important in everyone's life - but in particular mine - to have a goal. To have a purpose," he says.

This has the distinct sound of a surface being scratched, but if psychoanalysis about water therapy is going to be applied to this case study, it's not going to be Brown who does it.

In taking on this grand swim he says he's been motivated simply by wanting to feel motivated.

"And I don't really like running. In fact I hate running," he says.

"Also, once I make up my mind on something, that's it, I don't change it." .

To give himself the best chance of making it, Brown has enlisted the seven-time women's world marathon swimming champion and successful English Channel crosser Shelley Taylor-Smith.

A family friend, she has been Brown's coach for the past year and a half. Whether for 10, or 20, hours after her pupil gets the official green light to swim– Brown's expecting he will be setting off on Saturday morning, Dover time - Taylor-Smith will travel alongside him in one of the specially charted boats that's mandatory for the exercise.

She will control his eating and hydration, write notes on a whiteboard, and likely jump in to swim near for a period if his stroke rate wanes.

Brown's training program has been a five-day-a week occupation.

He had no set times for clocking his daily distance, and the only pre-swim fixtures were coffee and newspapers.

Swims could last one hour. They could last for six. His longest were 20-kilometre epics, and he managed two of them. Brown says he simply couldn't have prepared the way he has with a Monday-Friday job.

A diet around thrice daily protein shakes, plentiful potato cakes, ice cream, stout before bed, his first ever serve of McDonald's and two serves of every dish at functions, where possible, might sound appealing to some. But you can almost hear the gut churning in Brown's once-taut stomach at the raising of this essential forced ingestion of fat.

He doesn't think about much at all while swimming, save for a few footy ideas he might use in his Saturday television and radio commentary, and focusing on his technique.

"That's part of it," he says.

"You've just got to get into a zone and switch the mind off; not think too much."

Brown's most significant preparatory event was the 20-kilometre Rottnest Island swim.

"There were bad conditions, so don't laugh. It took me 10 hours and 28 minutes, which was slow," he says.

"But I made a couple of mistakes and it was pretty tough work. Every time I stopped to drink, the south-easterly pushed me backwards. So I probably did 23 or 24 kilometres that day."

Before operation English Channel, the greatest personal physical challenge Brown cites was his rehabilitation from a fractured pelvis that "literally snapped in half" during a football match in round 20, 2011. The other limit-pushing moment he tables was on a training camp he attended in Flagstaff, Arizona, with the Suns in 2013. In atrocious conditions - we're talking snow and 100km/h winds - the group tried to climb Humphreys Peak (elevation 3852 metres).

Three-quarters of the way up, the tour guide excused one and all from taking on the summit. Most of the group turned back, but Brown and a handful of others carried on (minus the tour guide). Brown nearly lost a thumb through frostbite, but completed the climb.

In his football retirement, Brown and wife Jess have opted for a quieter existence, after their stint on the Gold Coast. They live on a eight-hectare property 50 minutes north-east of Melbourne, at Kangaroo Ground, keep a couple of retired racehorses, miniature ponies, a dog, a cat and alpacas. Growing vegetables is on the agenda.

Through the swim preparation, Brown has raised more than $100,000 for underprivileged and sick Australian children. He's donating the money to the Shane Warne Foundation, which distributes grants in the field. The cricket legend has been a friend of Brown for about a decade, with the men sharing a fondness for poker playing.

Remarkably, for all the mental and physical effort invested by wannabe Channel swimmers, arriving at their strictly scheduled week-long allotment does not guarantee their swim will even take place.

They're at the whim of greater forces that must be assessed by an accredited captain. If your week falls in a week of storms, bad luck. The choice is to re-join the queue (the lucrative Channel crossing business spans three months annually), or walk away.

Brown's swimming window was booked 16 months ago. It opened on Wednesday July 8 and closes – strictly - on Wednesday July 15. His healthy support crew in Dover includes his wife, father, mother, sister, cousin and a handful of old friends.

In the worst-case scenario that Brown does not get his boat captain's nod, he says there is zero chance he would re-apply for the attempt.

A hell of a task awaits. Brown, though, makes it sound straightforward:

"I look at it like I looked at studying: I didn't like studying, but I wanted a degree. It took me nine years, but I got the degree," he says.

"My mindset is once you start you don't stop. I'm starting this swim at Dover, I have to finish in France. And the only way to finish in France is to swim there."