A Sussex MP has called for a privately-run patient transport service to be brought back into the NHS.
Coperforma has faced intense criticism since taking over the non-emergency hospital transport service in April.
Patients say they have experienced delays reaching appointments and sub-contractors have said they were not being paid.
Huw Merriman, Conservative MP for Bexhill and Battle, said: "I don't believe that contract works."
Speaking to BBC South East Politics Show, he said: "I would like to see that contract brought back in house so that ambulance services [were operated] within the NHS."
Gary Palmer, of the GMB union, said: "I think it's exactly what needs to happen. Clearly the move into the private sector has not worked in this case. The only option is to bring it back into the NHS family."
Coperforma said it was committed to providing patients and hospitals with an "unrivalled" ambulance service, and it would firmly oppose any action to have it taken away.