With the next 48-hour strike by Greater Anglia train guards due to start on Wednesday morning, the company still does not know what services it will be able to run.

It is planning to run a full service but after talks last week with the government’s official watchdog, the Office of Rail and Road, there has been no final permission granted so far for stand-in guards to operate services.

The ORR became involved in the issue after there were safety concerns the last time the guards walked out at the beginning of October.

The company was confident at the end of those talks that they would be able to use stand-in conductors on its services during the next strike – and have made plans for the strike days on that basis.

However because the ORR has not formally given its permission yet, passengers have no certainty about what trains will run on the two strike days.

Whatever happens 60% of Greater Anglia’s trains will run.

Suburban trains, including some from Ipswich to London and most from Colchester to London, are driver-only operation and do not need a guard.

However Intercity trains, rural services and trains to Clacton and Sudbury do have guards and would be affected. A small number of these services might be able to run – but if the stand-in guards were not allowed there would be many cancellations.

A decision from the ORR will have to come on Tuesday and will be publicised as soon as it is clear.

A spokeswoman for Greater Anglia said: “We’re in the process of concluding a comprehensive review of our arrangements with the ORR and we expect to conclude that process soon.

“We are planning on the basis that we will be running a full service on Wednesday/Thursday 8/9 November.”

During the two one-day strikes at the beginning of October the RMT said there were a number of safety incidents, including one where a stand-in guard opened the doors on the wrong side in Ipswich station leading to two members of the public jumping down on to a path next to a platform.

This led the Office of Road and Rail, the government’s transport safety watchdog, to tell the company it needed to see and approve its proposals to use non-guards who had been trained to operate services on strike days.