Ireland's former richest man, Sean Quinn, was declared bankrupt on Friday after having bet the family fortune on the shares of Ireland's most notoriously profligate bank just before it collapsed.

Quinn, 64, developed a quarrying operation in the northern county of Fermanagh in 1973 into a global organisation with insurance and property interests.

He amassed a fortune of 4 billion euros (3 billion pounds), before investing massively in the now failed Anglo Irish Bank, one of the biggest casualties of Ireland's property bubble.

It is with great sadness and regret that I have applied for voluntary bankruptcy in the High Court in Belfast today, Quinn said in a statement. A court spokesman confirmed the court had declared him bankrupt.

He doesn't have any ability to pay his debts at this time, Quinn's solicitor, John Gordon, told Ireland's state broadcaster RTE. He is left with very minimal assets.

At the height of the Celtic Tiger property boom in 2008, the Sunday Times rich list named him Ireland's richest man with a fortune then estimated at 3.73 billion pounds, worth 4.7 billion euros at the time.

Quinn was known for jetting around eastern Europe with a team of lawyers to seal multi-million-euro property deals, but he kept a much lower profile than many of his fellow property tycoons, with few conspicuous displays of wealth.

At its peak the Quinn Group employed more than 5,500 people on both sides of the Irish border and had substantial property assets in Russia and Ukraine.

A disastrous investment in Anglo Irish shortly before it collapsed under the weight of failed property loans cost the Quinn Group more than 1 billion euros. Anglo says Quinn and his family owe it almost 2.9 billion euros.

Quinn stood down as chairman of Quinn Insurance in 2008 after the financial regulator fined him 200,000 euros and the company 3.25 million euros, over loans it had issued to a related company.

Quinn Insurance was placed into administration in March 2010 after the regulator said it was not meeting solvency requirements.

Quinn is still regarded as a hero in his home country for creating thousands of jobs and locals have held rallies in recent months to show their support.

Anglo Irish, recently renamed Irish Bank Resolution Corporation (IBRC), is being wound down after swallowing 29 billion euros ($40 billion) of state capital.

IBRC said in a statement that it was examining the validity of the bankruptcy claim outside of Ireland and would continue to pursue maximum recovery of Quinn's debt. The United Kingdom's bankruptcy laws, which apply in Belfast, are more lenient than those in Ireland, where it can take 12 years to emerge from bankruptcy.

(Reporting by Ian Graham and Conor Humphries; Editing by Michael Roddy)