Eurotunnel has been urged to implement a new radio technology system "very quickly" because operators using the Channel Tunnel have been unable to communicate remotely with on-board managers when trains are in the tunnel.

The company, which operates the tunnel, in December signed a €21.5 million (£18.9 million) contract to upgrade the Channel Tunnel communications system, just days before heavy snow near tunnel entrances led to trains breaking down in the tunnel.

The trains were out of reach of radio signals for remote customer communications systems, meaning the train crew could not receive the information they needed to keep passengers informed on what was happening.

The new radio system, from supplier Alcatel-Lucent, will be used to improve communications with trains in the 31 mile tunnel, but will not be operational for another two years.

An independent review was commissioned on what happened and how Eurostar, the train operator that pays Eurotunnel to use the track, dealt with the situation. It found that an inadequate communication system in the Channel Tunnel, managed by Eurotunnel, played a significant role in the chaos that angered passengers.

Train staff had seemed unaware of what was happening, passengers had said, while the trains were stuck in the tunnel and drivers were tackling the technical problems.

The only communications infrastructure available was a radio link between the train driver and the Eurotunnel Rail Control Centre (RCC), used to provide technical and operational advice to the driver in the case of breakdown. It does not link to Eurostar’s own control centres, the Eurostar Independent Review found.

The report criticised Eurostar for the "appalling" conditions, and for other failures including not protecting its engines from the weather. Some 2,500 passengers were stranded in the tunnel for up to five hours.

The report urged the companies to take action by examining the introduction of an alternative communications system while it waits for the 2012 rollout of the Alcatel Lucent GSM-R technology, which will digitise and record communications. It also said the GSM-R system then needed to be introduced "very quickly" with the right configuration to improve customer communication.

Eurotunnel said in a statement that the GSM-R contract it signed with Alcatel-Lucent "could, if Eurostar so wishes, be extended to GSM-P public communications". This would allow Eurostar to communicate with its train managers in the tunnel, using GSM technology on its trains.

Eurostar has pledged to invest over £30 million to improve its trains, passenger care and communication inside and outside the Tunnel. A spokesperson said: "Our people were talking to the RCC, but not to the people on the train. Until the train comes out of the tunnel there were no mobile communications."

The review said better communication links were needed between Eurostar and Eurotunnel’s RCCs based at the terminals in Folkestone, Kent, and Coquelles, Pas-de-Calais.

Severe weather in France and the UK also meant that Eurostar struggled to get to the control centres in order to communicate with passengers. "We had as many people there to help as possible. We do accept that it was insufficient," said a spokesperson.

Last night, an unidentified "technical problem" stopped another Eurostar train from working. But the company was able to communicate remotely with its crew as the train was outside the tunnel, in Ashford.