Junior doctors are waiting to hear whether England’s High Court will agree to stop the government imposing a new contract.
The group Justice for Health says it mounted the legal challenge because the contract is “unsafe and unsustainable”.
The Department of Health says the case is without merit.
Ministers insist the new contract is needed to improve levels of medical cover in hospitals at weekends so that the NHS can deliver seven-day services.
The dispute over the contract, which is due to be rolled out from October, has already led to thousands of hospital operations and appointments being cancelled during a series of junior doctor strikes.
Junior doctors had planned a run of five-day strikes in the four months leading up to Christmas, but recently called these off following concerns over patient safety.
In May, it looked as though a breakthrough had been reached in the dispute after both sides agreed to a new deal.
But the government announced in July that it would impose a new contract after junior doctors and medical students voted to reject the deal.
The High Court will consider three areas:
- the lawfulness of the imposition of the contract
- whether Health Secretary Jeremy Hunt had properly informed the public and Parliament about the plans
- the evidence behind Mr Hunt’s proposed changes
The medics argue that, although Mr Hunt is entitled to “recommend” a new contract, he is attempting to go significantly further even though he has no power to decide the terms and conditions under which the NHS and other bodies should employ junior doctors.
Meanwhile, the British Medical Association has invited the health secretary to take part in a conference this autumn to discuss ways to make care more consistent over the whole week.
Mr Hunt had argued the new contract was needed to help create more seven-day services in the NHS.
In a letter to the health secretary, the union said it was made in “good faith” to try to find solutions to some of the issues raised during the long-running dispute.