The Prime Time Investigates programme followed a driver who spent his days driving a Dublin bus and his nights driving a taxi, with very little sleep.
It also reveals that there are 'rogue' multiple-licence operations which will rent a taxi to anyone for a weekend for €100, even if they have no taxi PSV licence.
And the investigating team also reports on how payment of €100 ensured the passing for NCT of vehicles which had been failed a short time before.
The programme is being broadcast at 9.30 on RTE 1.
