Weston General Hospital has been accused of abusing the strike deal to get junior doctors to return to work.
The British Medical Association (BMA) says it was told staffing levels at the Weston-super-Mare hospital were dangerously low.
But the BMA has now called the doctors back onto the picket line, claiming the hospital was either unaware it actually did have sufficient cover or deliberately misled the union.
A spokesperson said: "We have revoked the derogation granted to Weston General Hospital.
"It has become apparent that both the BMA and NHS England were misled over the level of staffing cover. Either local management were unaware they had sufficient senior cover, or they deliberately misled us.
"We will be asking NHSE to explore any potential probity issues. We granted a derogation in good faith and it is incredibly disappointing to see this abused in this way.
"We are grateful to our consultant and SAS colleagues for their hard work providing cover during the strikes."
Hospital had 'concerns about risk to patient safety'
In response, the chief executive of University Hospitals Bristol and Weston NHS Foundation Trust Professor Eugine Yafele said: “The safety of patients is our top priority.
"When applying for the derogation we provided information requested by the BMA that accurately reflected our concerns about risk to patient safety, during what is a fast-moving situation. These concerns were supported by consultants providing cover.
“As part of our established operational planning for periods of industrial action we’ve been exploring all avenues for ensuring sufficient cover for key services over the course of the week, as well as each day responding to unplanned absences.
“In doing so, we are very grateful to colleagues who have stepped in to provide medical cover, which has made the difference in ensuring that we have sufficient staffing without ultimately having had to draw on the derogations.”
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