Musicians in the West End production of War Horse are seeking a court order preventing the National Theatre from replacing them with a pre-recorded soundtrack.
All five were made redundant from the show's New London Theatre run last month after the NT terminated their contracts.
The NT, which also has productions of the multi-award winning show touring the UK and the US and another playing in Berlin, says it made the decision for artistic and financial reasons.
Today, at London's High Court, James Laddie QC, acting for Neyire Ashworth, Andrew Callard, Jonathan Eddie, David Holt and Colin Rae, asked Mr Justice Cranston - who revealed he had not seen the show - for a temporary injunction preserving the status quo until the case can be tried.
The musicians, who were engaged in March 2009, were given 11 days notice and continued until recently with the "charade" of turning up at the theatre and being turned away again, he said.
"The claimants have not accepted this breach of their contracts, and have elected to affirm their contracts. They have at all times made it clear that they remain willing and able to attend work and to perform their obligations under their contracts."
The NT first said it planned to move to recorded music in late 2012 and the musicians' role was reduced after March 2013 to three or four minutes until stopping altogether on March 15.
In its letter to them last month, the NT said: "The reason for your redundancy is that we wish to bring the London production into line with other productions of War Horse that now exist, and this is the wish both of NT management and the creative team."
Mr Laddie said that the musicians were not asking to go back to the pre-March 2013 position but to where they were a few weeks ago: "Even a small walk-on role is better than nothing. It is perhaps an indication of how tough the musical world is that they are happy with that - happy being part of an ensemble, being associated with War Horse and picking up regular wages week in week out.
"All of those are reasons why they want to keep the contract alive."
Mr Laddie said they had not just suffered financial losses but also the loss of security, interest and pride which came with being engaged in a runaway commercial and critical success to which they had made a major contribution.
They were familiar with the arrangements and capable of adapting their performances to take account of any alterations in artistic direction.
"As at April 1 2014, their roles within the show have not been replaced by actors. Further, their instruments remain in the band room.
"There is no reason why they cannot be reinstated with ease, and there would be no displacement of any other performer when doing so. They would require only a single short rehearsal.
"The cast and crew of War Horse are likely to be delighted to welcome them back."
He said that it was practically unthinkable that any other production in which any of them might work would enjoy anything like the success or longevity of War Horse - and their case was that they were entitled to remain with the show until the end of the production.
"Given War Horse's extraordinary success, that is not likely to happen any time soon."
David Reade QC, for the NT, said it appeared to be the musicians' case that they were entitled to remain part of the play even where there was no role for them in it.
The company was permitted to terminate their contracts in circumstances where there was no longer a need for their services because there was no longer to be an orchestra as part of the production.
As shown by the Lawrence Olivier and Tony awards it had received, War Horse was a play that had music - rather than a musical like Phantom Of The Opera.
Although there was a score, the band was only visible on stage for a very small part of the play and any music played was mostly piped in from a different room.
"As such, the orchestra was not an integral part of the play, and indeed there is no live band in any other production around the world."
If the order was granted, it would impact on those involved in the artistic and creative direction of the show, who had as much right to freedom of expression as the musicians.
As of March 17, there was a new cast and the show was staged and lit without the presence of musicians.
"I am told it takes seven weeks to rehearse a three-hour play so the suggestion it could be restored in a few hours when people's roles have been tracked is frankly naive."
The NT did not question the musicians' ability but believed that a live band did not provide the same quality of performance as could be achieved through the use of recorded music and professional actors.
It also enabled savings to be made which allowed the budget for live music to be deployed where it had the greatest impact.
If the musicians were reinstated, their presence would be imposed on the production "under sufferance" and there could be no suggestion of any "kudos" in being part of the play in those circumstances.
The judge said he would give his decision next Tuesday morning.