It comes as figures show the number and success rate of claims following disruption varies widely across Britain, with Scotland’s main operator’s lagging below average.

Refunds– known as Delay Repay– are only available to ScotRail passengers for delays of more than 30 minutes, in line with most companies.

However, eight firms give money back for hold-ups of more than 15 minutes.

There were 64,090 claims submitted to ScotRail between April and October last year, with 78 per cent approved, compared an average of 84 per cent. By comparison, the similarly-sized north England operator Northern, which uses the 15-minute threshold, received 132,246 claims. A total of 77 per cent were approved.

ScotRail passengers can claim back half their ticket price for delays of 30 minutes or more, and a full refund for those of an hour or more.

The Scottish Government’s Transport Scotland agency said the 15-minute option did not exist when the ScotRail franchise was let to Abellio in 2014.

The agency said that since then, it had been introduced at other operators as new franchises started. ScotRail’s is due to be re-let from 2025.

A spokeswoman said: “There are no immediate plans to reconsider this, although we are aware of developments and it will form part of the thinking when we re-franchise.”

However, official passenger watchdog Transport Focus called for swifter action.

Scotland-based senior stakeholder manager Robert Samson said: “While Delay Repay 15 compensation has been rolled out by many operators, ScotRail passengers are left out of pocket each year.

“Train companies and government must do more to accelerate the pace at which this is introduced.”

Campaigners Railfuture agreed.

Spokesman Bruce Williamson said: “We already have a complex and confusing ticketing system on the railway, and different rules for compensation on different lines is only likely to deter passenger from claiming.

“Fifteen minutes seems like a reasonable threshold for payment, whichever line you’re on.”

A ScotRail spokesperson said: “We will provide customers with money back on the cost of their ticket for delays of 30 minutes or more, which is over and above the industry standard [of 60 minutes].”

However, it said claim success rates would not necessarily increase if the 15-minute threshold was introduced because some would still be rejected for other reasons.

These include if the delay was known prior to the ticket being bought, or during temporary timetables.

Calls for ScotRail to introduce a more generous refund system for delays