Permanent chiefs are yet to be appointed at the city's two main hospital trusts.

The former chief executives at North Bristol and University Hospitals Bristol trusts resigned almost four months ago but replacements are still to be found.

Sonia Mills left Frenchay and Southmead hospitals after seven years at the helm.

And Dr Graham Rich moved on from University Hospitals Bristol NHS Foundation Trust (UHBristol), which runs the royal infirmary and eight other city-centre hospitals.

Announcements were made about the resignations back in December.

Miss Mills left to become chief executive at NHS Oxfordshire but Dr Rich will remain at UHBristol working on a research project into how the hospitals provide services for people across the city.

While interim chiefs have taken over at both trusts, there has so far been no sign of new permanent bosses being appointed.

Director of operations at North Bristol Trust (NBT), Ruth Brunt, has stepped in as interim chief executive while at UHBristol director of corporate development, Robert Woolley has taken over.

NBT said it would be advertising for a new chief executive at some point in the future.

At UHBristol, chairman John Savage said he was working with recruitment agencies to find a candidate for the role and hoped to have a chief executive in post by late spring.

He said: "Appointing the right person to lead UHBristol is vital for our future.

"As one of the largest teaching and research hospitals in the South West, we will continue to focus on providing excellent patient care.

"I am working with specialist recruitment agencies to ensure that we can attract a high-calibre candidate to lead the trust into the future.

"We hope that a shortlist will be considered in the next few months and an appointment can be made in the late spring."

Since the two resignations were announced within weeks of each other, rumours of a potential merger between the hospitals took on new momentum.

On her last day at NBT, Miss Mills told the Evening Post that a merger of the trusts would be a good idea.

She left the trust to join NHS Oxfordshire as chief executive but remains interested in goings-on in Bristol as she grew up in the city.

Miss Mills said last month: "I've always thought that would be a very good idea. I think it would make a great deal of sense for the future.

"It does affect finances as you deliver services across two organisations. It's potentially easier to do that within one organisation, although it would be large."

Despite rumours of a merger, the NHS has said there were currently no plans for the two trusts to be combined.