The security firm which transfers prisoners to courts in Scotland has been late on nearly 22,000 occasions since taking over the contract at the start of the year.
Between January 10 and September, G4S was late in bringing prisoners to court 21,735 times, resulting in financial penalties of £334,500, figures from the Scottish Prison Service show.
G4S is the firm which was at the centre of the London 2012 Olympics staffing fiasco, when Armed Forces had to be drafted in because the company failed to supply enough staff.
The figures were revealed by the Scottish Government in response to a written question from Labour.
The party's justice spokesman Lewis Macdonald said: "These figures show just how shoddy the basic service being provided by G4S is. I'm only relieved that they are being hit in the pocket for their poor performance.
"Scottish Labour again calls on the Scottish Government to stop awarding contracts to the company until their performance can be shown to be much better than it is at present."
A Scottish Prison Service spokeswoman said: "The number of delays to court business as a result of late deliveries of prisoners to court in the past 11 months has been very small and there has been a significant improvement in delivery performance since the contract became operational in January."
A G4S spokesman said: "Since taking over the contract for prisoner escorting in January 2012, G4S has been working to reduce the number of historical late deliveries to courts.
"We have retrained staff and introduced new G4S procedures and our client, the Scottish Court Service, has noted a significant improvement in performance since the contract became operational.
"In the six months from April to September, there has been a reduction of about 40% in the rate of late deliveries to court. While we are not complacent, this is encouraging progress and we will continue to work with our staff and our partners to ensure that this continues."