It’s astounding that former billionaire Nathan Tinkler has wound up at the centre of an Independent Commission Against Corruption investigation into donations to the Liberal Party.

The controversy surrounds his attempt to get approval for a massive new coal loader to be built on the former BHP steelworks site at Mayfield in Newcastle. A lot of lobbying was necessary, because the loader idea was never going to stand up on its merits; it went against a decade of planning underway since the Mayfield site was vacated by BHP in 1999.

The site was zoned for a mix of light industrial and commercial uses. The company proposing the coal loader was Buildev, a successful Newcastle-based property development and construction firm in which Tinkler bought a minority stake in 2008. Buildev had won a state government tender to develop part of the site a year earlier. Nobody had expected a coal loader would be proposed there.

Tinkler’s loader concept was first revealed publicly in December 2010. At the time, Tinkler was at the height of his wealth and influence. OK, it was touch-and-go, but in August he had pulled off his second deal of a lifetime: his major company Aston Resources had bought the Maules Creek project in the Gunnedah Basin from Rio Tinto for half a billion dollars and floated it at a valuation of $1.2 billion within nine months, and its shares were rising.

Tinkler had no ready source of cash flow, however. Maules Creek was just a proposal, years from production (and the project, now owned by Whitehaven Coal, still is not built). On paper, according to BRW, Tinkler was worth $610 million at the end of 2010, mainly due to the value of his one-third stake in Aston. But Tinkler was already reliant on borrowings against that stake to fund his empire and everything he owned was costing him money, not making it: his mining interests were all early-stage development plays, he was burning cash on mansions, fast cars and private jets, and he had sunk $200 million-plus into the beloved Patinack Farm horse stud spanning three states, with no sign of a return. Tinkler’s welcome — but expensive — takeover of the Newcastle Jets and shortly the Knights would only hasten the outflow of cash.

This was nothing new for Tinkler: right across his empire, right from the beginning, there was an almost permanent cashflow crisis. Which is one reason why it is difficult to believe cheques worth thousands of dollars were often signed without Tinkler’s knowledge. There would have been grim laughter up and down the Hunter Valley yesterday when Tinkler’s chief financial officer Troy Palmer was asked about a same-day payment he authorised to the Liberal Party, and denied this was unusually prompt: “When other employees and people ask for payment, I’ll pay it,” he testified, without a hint of a smile.

Tinkler had another problem: Aston had to get the Maules Creek coal to market. Tinkler only went public with his coal loader proposal in December 2010, after Aston got less than half its expected allocation of port capacity from Port Waratah Coal Services, owned and controlled by BHP and Rio Tinto, operator of two terminals at Newcastle. Aston complained about anti-competitive behaviour to the competition watchdog but was rejected. For Tinkler, it was another demonstration of the power of the incumbents he was determined to outsmart, as his mentor, the late Ken Talbot, had done. Tinkler’s grand vision was to create a new, vertically integrated coal business with operations from mine to rail to port, beholden to no one, and getting his own loader was absolutely key to the vision.

In late 2010, everyone knew Labor was headed for a wipeout in New South Wales. That did not mean, however, that the party’s sitting member for Newcastle, Jodi McKay, would lose her seat, which had literally been held by Labor forever.

“In truth, Tinkler was in Singapore. It was reckless — tantamount to flipping the court the bird.”

So the stakes were high when Tinkler met with McKay — ostensibly to discuss his bid for the Knights — and indelicately broached the subject of the coal loader, offering to donate to McKay’s campaign if she would support him. Tinkler knew — and the devastating emails and texts shown in evidence before ICAC suggests his executives Palmer, David Sharpe and Darren Williams also knew — it would be breaking the law if Buildev was to donate directly, under NSW laws banning developer donations introduced in 2009.

So Tinkler proposed giving from another of his companies. When his offer was rejected, it appears he helped fund production of an illegal leaflet — circulated after electoral writs were issued — which attacked McKay and undoubtedly hurt her re-election chances.

This is classic Tinkler — bullying, and as though he was above the law. Tinkler group employees were often sacked without having their entitlements paid. Contractual obligations to suppliers were routinely ignored. It took a while to emerge publicly, but the pattern was set very early in Tinkler’s career: if you wanted to get paid by Tinkler, you would have to take him to court.

Tinkler did his share of wheeling and dealing: he explored the possibility of investing in the controversial Mount Penny tenement in the Bylong Valley, at one point meeting with one of the Obeid sons, but ultimately decided against. One of his companies took a small minority stake in Coalworks, which had the Ferndale project, and he ended up in a joint venture with the Obeids — scoring an honourable mention in ICAC’s report into Operation Jasper. Aston executives Todd Hannigan and Tom Todd and their wives made personal political donations to the National Party which were not declared when the Maules Creek application was lodged, because the application was made by another subsidiary, Aston Coal 2. This was subject of legal action and Whitehaven has since copped a fine.

At the same time Tinkler was not a political animal, he was no schmoozer and did not move in political circles, and it is entirely plausible that he deferred to the much more engaged guys from Buildev, who had long experience lobbying like much of the property industry. Tinkler’s approach was relatively unsophisticated — his emails produced at ICAC show he believed that if you give the money, you get the outcome … within weeks. Tinkler’s own counsel, examining Darren Williams yesterday, was keen to establish this point: Tinkler relied on the guys at Buildev to handle the pollies.

Whether through ignorance or arrogance, Tinkler jeopardised his own interests by flouting the law: in early 2013, he was lucky not to have an arrest warrant issued against him, when he failed to respond to a summons from the Supreme Court, to appear in liquidators’ examinations for one of his shelf companies, Mulsanne Resources. Tinkler’s spokesman said he was in a hotel around the corner from the courtroom, ready to attend if required. In truth, Tinkler was in Singapore. It was reckless — tantamount to flipping the court the bird. On another occasion, he defied the receiver appointed by lenders to his aviation company and ordered his private jet to take off for Singapore.

But of course, Tinkler is not above the law. As McKay confirmed sensationally in ICAC last week, his approach to her could well be construed as an attempted bribe. Tinkler’s own appearance at ICAC has been put back — he is now expected to give evidence next week, before Operation Spicer is adjourned — but it is clear he has deadly serious questions to answer. Attempted bribery of a politician is a criminal offence; if convicted, Tinkler could go to jail.

We know about Tinkler’s rise. The agonising fall is still happening, right in front of us, and it might be harder than anyone suspected.