Train operator Chiltern Railways has issued strong guidance to customers to only travel if absolutely essential across the week in which the RMT union is taking industrial action.

The strike is in effect between June 21 and June 25.

On strike days (June 21, 23, 25) there will be "extremely limited" availability of staff, so Chiltern Railways will not be able to operate services on most routes.  

The train company says they will have "significantl less staff" to service and prepare the number of trains they would normally need. 

They added: "Coupled with the fact we are unable to position our fleet how we normally would, this means that we will have to operate a heavily reduced timetable on non-strike days during the week."

The strike action also means Chiltern Railways will not be able to provide travel to and from the Ed Sheeran concerts on June 24 and 25. 

And industrial action is taking place on the London Underground on Tuesday June 21, which will mean Chiltern Railways services will be unable to call at stations operated by London Underground. 

Eleni Jordan, Commercial & Customer Strategy Director for Chiltern Railways, said: “We are disappointed that the RMT industrial action, if it goes ahead, will bring severe disruption across our network.

"The action is also coupled with planned engineering work on the Chiltern mainline between Birmingham and Dorridge.

"We are calling on customers to travel only if essential between June 21 and 25 and seek alternative transport where possible. 

"We have worked tirelessly with our train planning team and industry partners to ensure that we can provide as many services as possible during the week that the strike action is planned – and keep people moving as best we can.”