GMB and Unison leaders pushing for better pay and conditions for their members say they are not satisfied with what their employer ISS Mediclean is currently offering.

ISS Mediclean, which has about 240 employees, is contracted to provide domestic and some portering services at Derriford.

GMB Union negotiator Gary Smith said there was still hope of a resolution to the dispute, but the firm had to produce an offer on paper.

"We are waiting to get the detail from the company on their offer," he said.

"We will then be consulting with our membership.

"If there isn't progress then unfortunately we shall be balloting for industrial action.

"We hope that the company, if needs be, will come back to the negotiating table."

ISS Mediclean told BBC News Online that a formal offer would be made to the unions by Friday.