Train users are being urged to travel only if 'absolutely necessary' next week, as rail workers are set to go on strike.

Great Western Railway (GWR) has announced its planned timetable for next week as industrial action by the RMT union at train operators across the industry and Network Rail is expected to severely affect services from June 21 to 25.

GWR said it will operate as many trains as possible during the strike action however, most train services will be affected on the days announced.

Due to the timing of the strike action, services between strike days will also be affected, the operator said.

On strike days, GWR is aiming to provide around 30% of its usual timetabled services, and about 50% on non-strike days.

Managing director, Mark Hopwood, said: "We very much welcome the opportunity to continue to talk with the RMT to avert strike action.

"Any strike will impact on customers' journeys and can only damage the post-covid recovery everyone at GWR has been working to win back, while at the same time making it more difficult to deliver the changes we need to secure jobs and services for the future.

"I'm hopeful the RMT will step back, however colleagues have been working hard to put contingency plans in place and give certainty to customers who need to travel.

"The priority will be to keep trains running and customers moving safely, but changes will be needed to allow that to happen and customers may wish to alter their plans."

Where trains are able to run, they are expected to be extremely busy and replacement bus services are not able to be provided.

On the days of strike action - June 21, 23 and 25 - GWR expects to only be able to operate services along the following routes and stations:

North Somerset Times: The routes GWR hopes to still operate on strike days next weekThe routes GWR hopes to still operate on strike days next week (Image: GWR)

On days when strike action is not taking place GWR expects to be able to operate the following reduced, service:

North Somerset Times: The routes GWR hopes to still operate on non-strike days next weekThe routes GWR hopes to still operate on non-strike days next week (Image: GWR)

Customers who have already purchased tickets can claim a full refund or can amend their ticket; those who travel and are delayed may be entitled to delay repay compensation if they are delayed by 15 mins or more.

Season ticket holders can apply for compensation through the Delay Repay scheme.

To help customers, GWR is allowing people with tickets for travel on strike days to be able to travel on the day before and up to two days after.

The firm's Refund and Book with Confidence policies remain in place.