Workers including caterers, cleaners and porters had voted overwhelmingly in favour of strike action in September but NHS England issued new guidance , external that “new subsidiaries involving the transfer of NHS staff will now only be approved in a limited number of circumstances”.

Unison general secretary Christina McAnea said: “The decision by the trusts to halt these plans will bring welcome relief to staff who feared their pay and conditions were going to be worsened.

“All NHS trusts need to follow this example and immediately halt plans to outsource staff. Those that don’t should expect to be met with a wave of opposition and industrial action.”

Staff had mounted protests throughout the summer and 97% had voted in favour of the most recent industrial action.

Siobhan Harrington, chief executive of University Hospitals Dorset, and Matthew Bryant, chief executive of Dorset County Hospital and Dorset HealthCare, said in their statement: “We know our unions do not support the proposal.

“We put huge value on the work of our staff in these services, and we will continue our discussions with colleagues and unions to find a way forward to provide the most effective and efficient services for our patients.”

Minister of State for Health and Social Care Karin Smyth, when questioned earlier this year , externalabout the proposal to use subsidiaries, said: “The government expects that any outsourced services are delivered by trusts in a way that improves quality, ensures greater stability and longer-term investment in the workforce.”