The RMT has called for a face-to-face meeting with transport secretary Grant Shapps and chancellor Rishi Sunak before rail strikes start next week.

The railways will be disrupted for three days when workers from Network Rail and 13 train operating companies take to picket lines in their dispute over pay and jobs. In a letter to Grant Shapps, RMT general secretary Mick Lynch says it has become clear that the Treasury is ‘calling the shots’ and is not allowing rail employers to reach a negotiated settlement with the union.

Mr Lynch wrote: ‘I am writing to seek an urgent meeting with the government, without any pre-conditions, to discuss the national rail disputes prior to the planned strike action next week and I would be grateful if this could be arranged without delay. As you will be aware both this year and last year, meetings have taken place under the Rail Industry Recovery Group.

‘It has become obvious in our discussions with employers since the RMT ballot result that the government is retaining control over the conduct of negotiations with the RMT, and the Treasury in particular is calling the shots. In effect in recent weeks the union has been negotiating with the government, but the government have not been in the room.

‘I also note the government have decided to have a parliamentary debate on the dispute today. So, as well as speaking at the despatch box, I hope you will be able to speak to me directly about resolving the dispute.’

Meanwhile many train operators have been issuing warnings about severe disruption next week, and Network Rail says it is in the closing stages of drawing up emergency timetables in which about one on five trains will run.

Network Rail is predicting that ‘thousands of specially trained and fully qualified back-up staff will step in to keep vital services running, but as they are a fraction of the usual workforce, only a severely limited service will be available’.

Where they do run, services will start later and finish much earlier than usual, running between roughly 07.30 and 18.30. In some cases last departures will be much earlier, to allow trains to return to depots. The last Avanti West Coast departure from London Euston, for example, is expected to be no later than 15.43. Only half the network is likely to see any services, with Rail Delivery Group chair Steve Montgomery predicting that ‘significant disruption will be inevitable’.

Network Rail chief executive Andrew Haines said: ‘Talks have not progressed as far as I had hoped and so we must prepare for a needless national rail strike and the damaging impact it will have. We, and our train operating colleagues, are gearing up to run the best service we can for passengers and freight users next week despite the actions of the RMT.’

Consumer watchdog Transport Focus said it is ‘passengers who suffer most’. Chief executive Anthony Smith added: ‘It is crucial that all parties keep current and future passengers in mind when trying to resolve this dispute. Passengers need plenty of advance information about the services that will and won’t be running to allow them to plan their journeys. They also need to know how to get their money back if they now won’t travel.’

Timetables for next week have started to be published, although changes remain possible.