NICOLA Sturgeon has condemned ScotRail after it emerged three in four trains on a popular commuter line are late or cancelled.

The First Minister said the performance of services on the Milngavie route was “not acceptable” and she expected rail bosses to take action.

It came as she face repeated questions over ScotRail’s performance during First Minister’s Questions.

Scottish Green MSP Ross Greer, who represents the West Scotland region, said passengers were stuck with a service they can’t rely on.

He said: “The latest ScotRail performance statistics show that on the Milngavie line, three in four trains are late or cancelled.

“Does the First Minister believe that ScotRail are fulfilling their obligations to passengers on a line where they can’t get three out of every four trains reliably?”

Ms Sturgeon responded: “No I don’t think that’s acceptable for passengers.

“That performance level is not acceptable, which is why we are working with ScotRail and it’s why we set stringent expectations for ScotRail to take the action that improves performance and improves the passenger experience.”

The First Minister also came under attack from Labour and the Tories over ScotRail’s record.

Scottish Labour MSP Colin Smyth said the operator had failed to fully deliver 29 of its franchise obligations.

He said: “Punctuality has plummeted to a new low with almost one in five trains running late. Passengers are sick and tired and deserve better.”

Ms Sturgeon said ministers “deeply regret” any inconvenience to passengers, but insisted around half of all performance failures were caused by Network Rail – which the Scottish Government is not responsible for.

Meanwhile, Scottish Tory MSP Jamie Greene brought up the case of a recent train service from Edinburgh to Helensburgh, which de-coupled and left three carriages stranded at Uphall station.

Ms Sturgeon said the incident was currently under investigation.