Tory council leader Martin Hill
Inspectors described most aspects of adult social care in the county as nothing more than "adequate" – to the fury of those running the service.
Lincolnshire County Council has now been slapped with a one out of three star rating every year since the current ratings system was introduced in 2002.
The authority's chiefs insist inspectors are ignoring clear improvements in services offered to elderly and disabled adults.
And they say they will stop co-operating with officials at the Commission for Social Care Inspection (CSCI) when they next come to visit.
Tory council leader Martin Hill accused inspectors of setting out to give a bad report regardless of the facts.
"This report is a load of rubbish," he said.
"I am really amazed that an organisation like this can do something so unfair.
"If it was football, it would be bringing the game into disrepute."
The council says it had been working closely with CSCI all year to improve standards, and had been given no indication that things were wrong.
The Labour opposition said it would have been "nice" to achieve a higher rating.
But they say appealing the decision through the courts would waste taxpayers' cash.
Labour group leader Rob Parker said: "We should simply accept the decision of the inspector and concentrate on improving care."
For a full report see Wednesday's Lincolnshire Echo.