The leader of the Labour group on Worcestershire County Council has been illegally serving as a councillor for five years.
Peter Pinfield, a former leader of Droitwich Town Council and chairman of Worcestershire social services, was immediately disqualified as a councillor on the eve of yesterday's council elections when it was discovered his job as social services manager in Dudley was politically restricted.
He hopes to be immediately reelected today , after he was forced to take a job demotion, but The Birmingham Post understands the county council will be forced to call a by-election even if he wins the Droitwich Town ward.
Mr Pinfield's employers were informed of Mr Pinfield's position by an unknown party and, in turn, Dudley Metropolitan Borough Council investigated and informed WCC last week.
He reached a pay scale in 2000 which meant that under legislation introduced in the late 1980s he was unable to hold political office.
Last night Mr Pinfield, who will be allowed to take a pay cut by his employers, said: "I recognise there may be a challenge if I win the ward. It has all been a huge mistake and as soon as I and WCC found out about it, we acted immediately." Mr Pinfield did not know who informed Dudley Council.
"As soon as I became aware of the problem I accepted that I had to stand down," he said.
Andrew Sparke, chief executive of Dudley Council, said: "It's all a bit of a mess, frankly.
"Mr Pinfield has been at that salary scale for five years but the conflict was only brought to our attention recently.
"Our legal advice is that only until such time as the demotion takes effect will it be legal for him to stand.
"Therefore when his nomination for the Worcestershire election was entered, he was not legally able to stand.
"If he wins, a by-election will have to be run. By that time he will be able to stand."