Passengers have been warned of further significant disruption across train services in Scotland due to continued strike action from railway staff.

Network Rail’s RMT members will take part in a 24-hour strike on Saturday across the UK railway network amid an ongoing dispute over pay and conditions.

The action will impact services north of the border as many staff members walking out occupy safety-critical roles and, as such, ScotRail said the “vast majority” of trains will not run on the day.

The train operator warned further disruption will happen on Sunday due to signal boxes across the country opening at different times throughout the day following the strike.

Around half of the UK railway network be closed all day, and trains will only operate between 7.30am and 6.30pm.

It means only about 20% of normal train services will run on the day, Network Rail said.

Tim Shoveller, the train operator’s chief negotiator, urged passengers to “only travel by train if absolutely necessary”.

Services across the UK will also start later than normal on Sunday morning as workers return to duties.

More than 40,000 members of RMT at Network Rail and 15 train operating companies are expected to take part in the industrial action.

Phil Campbell, ScotRail’s head of customer operations, said: “We’re really disappointed that the dispute with the RMT has reached this outcome, given the strength of the improved pay offer ScotRail made.

“This strike action does nothing for the railway’s recovery at this fragile time.

“It will severely impact our customers and it will also cost our staff through lost wages.”

In a separate dispute, the RMT announced that some of its ScotRail members will take part in 24-hour strike action on Monday after rejecting the latest pay offer.

Due to the number of staff striking, the train operator will have to run “very limited” services on just three lines on the day.

Trains will be limited to 7.30am to 6.30pm between Milngavie and Edinburgh via Bathgate (two an hour) and one train an hour between Glasgow and both Lanark and Larkhall.

Mr Campbell added: “Due to the large number of ScotRail staff who are members of the RMT, ScotRail customers should expect significant disruption to services on Monday October 10, as we won’t be able to operate the vast majority of our services.

“We’re advising customers to seek alternative means of transport and to only travel if they really need to on Monday, October 10.

“We remain open to resolving this dispute.”