ScotRail’s performance level is at its lowest since the franchise began, according to latest figures.
An official report published by the company showed 81.8% of services were on time between September 16 and October 13.
It comes as a freedom of information request revealed ScotRail’s performance benchmarks had been waived until June 2019 by Scottish Transport Secretary Michael Matheson.
The waiver included the caveat that “any further drop-off in performance will be unacceptable”.
The figures also put ScotRail’s Moving Annual Average for punctuality at a franchise low of 87.5%, below the agreed breach level of 88.22%.
ScotRail was fined more than £2.2 million for performance breaches in the first half of 2018.
The party’s Transport spokesman, Colin Smyth MSP, said: “These are shocking figures, but it is little wonder performance is plummeting after the SNP gave ScotRail a licence to fail until June next year.
“Far from being punished for their failings, ScotRail are being let off the hook.
“Enough is enough, passengers deserve better than the contempt being showed to them by ScotRail and the SNP Government.”
ScotRail Alliance managing director Alex Hynes said significant disruption was caused by strong winds during Storm Ali in September.
He added: “Everyone at ScotRail and Network Rail worked flat out to keep people moving and to get services returned to normal as quickly as possible.
“We are investing billions in improved infrastructure and hundreds of millions of pounds on new and upgraded trains as we continue to do everything we can to improve performance.
“It’s part of our plan to build the best railway Scotland has ever had.”