Hackney cab driver Steven Boyle was happy enough to have made a bumper £50 from the generous punter for the three-mile journey from Gunwharf to HMS Bristol on Whale Island.
But he realised he had done even better than that, when he discovered the lucky gambler had left his wallet containing about £2,000 on his back seat.
After spotting the wallet, Mr Boyle returned it to his grateful passenger and received a further £40 for his troubles.
Mr Boyle, of Jervis Road, Stamshaw, said he picked up the passenger near Gunwharf at about 4am yesterday morning when he was just beginning his shift.
'He said he was a medic for the marines but I didn't get his name. He said he'd just won £2,000 in the Grovesnor casino. He gave me a £50 note for the fare and I told him I couldn't change it as I had only just started for the day. He said, "I ain't talking about any change."'
Mr Boyle said he hoped the story showed that cabbies were an honest bunch.