Campaigners fighting for improved services on an overcrowded rail route have issued a crisis bulletin that says the train service is on the brink of collapse.

The Barking – Gospel Oak Rail User Group claims there are not enough trains for a viable service and that Transport for London has no idea when new trains will be fit for service.

The group is calling on the Mayor to take action to restore a reliable train service and demanding compensation for “years of misery”.

A statement from the rail campaign group said: “The service has been on a knife edge since mid-November when a diesel unit was lost.

“Transport for London cut two unit diagrams from the weekend schedule to allow time for maintenance for the six remaining units, giving irregular 15 and 30 minute intervals on those services during the weekend.”

The campaigners further claim the supplementary bus services are confusing and ineffective.

The new London Overground trains are delayed by one year on the Barking - Gospel Oak Line and by six months late on the Chingford Line as well.

Rail user group secretary Glenn Wallis said: "The line carries 10,000 passengers a day according to statistics from 2016 so it's a hugely busy line.

"Travellers have now had three years of disruption with no idea when the new train is going to enter service.

"There is already extreme overcrowding and if there are any cancellations going forwards, things will simply be completely intolerable."

Mr Wallis added that the group had met with TfL in November, but that the situation had not been rectified which was "completely exasperating".

He said: "What frustrates us is that TfL has seen this coming for most of the year but they've completely failed to come up with any alternative plan to guarantee continuity of the rail service.

"By mid-March there won't be any trains at all to run the service

"So basically we are exasperated and frustrated with TfL for doing nothing to avert the situation and secondly we also think it is outrageous that despite three years' construction, rail users have been offered nothing in the way of compensation."

Mr Wallis claims that this was more frustrating as up to September, TfL has received £5 million in penalty payments from Bombardier for non-delivery of these trains.

He added: "There is plenty of money coming in, but TfL are not spending much of it on the passengers, and on top of that, these payments are still continuing because the payments have not been delivered yet."

The group are asking for TfL to take "urgent, effective steps" to operate the service and offer compensation to passengers who have faced disruption.

Rory O’Neill, TfL’s general manager for London Overground, said: “We are sorry for the continuing delay to the introduction of the new fleet of trains on the Gospel Oak to Barking line. The manufacturer, Bombardier Transportation, have advised that they need more time for software development.

“We share our customers’ frustration and continue to push Bombardier to do everything they can to allow us to bring the new electric trains into service as soon as possible. We are working with Arriva Rail London so that driver training can start as soon as the software issues are resolved.

“Given the continuing delays we are now exploring the option of modifying other electric trains in our fleet for temporary use on the Gospel Oak to Barking line.

"There are a number of considerations that need to be resolved before we can confirm whether this is possible.

"We are testing a modified train on the line and expect to make a decision on whether it is possible to operate it later this month. It would operate alongside the existing diesel trains.”