The British National Party candidate mistakenly elected after votes were counted twice will take her seat on Birmingham City Council after local authority lawyers said they had no powers to declare the result invalid.
Sharon Ebanks was declared the winner of one of two vacant seats in Kingstanding ward after local election votes were counted on Thursday night and will be able to claim her #15,000-a-year allowance as a backbench councillor.
Council officials realised almost immediately that tellers had double-counted the votes cast for Mrs Ebanks following confusion over the number of seats being contested.
Under the Representation of the People Act, however, an election result is legally binding once it has been announced by the returning officer.
Mrs Ebanks, of Fell Grove, Handsworth, can only be removed from office if the defeated Labour candidate, Catherine Grundy, is successful in raising an election petition at the High Court - a process that could take months to complete.
Angry council leaders yesterday ordered an inquiry into the mix-up and said they would encourage Mrs Grundy to use the courts to take her rightful place on the council.
Mike Whitby, the Conservative leader of the city council, said it was "abhorrent" that the far-right BNP could end up with a place in the council chamber even though its representative had trailed in third place behind Mrs Grundy and Zoe Hopkins, who won the other Kingstanding seat for Labour.
Coun Whitby (Con Harborne) added: "It is going to take some time but we have to go through the law. The moral high ground lies with Mrs Grundy, who should be representing Kingstanding."
Deputy council leader Paul Tilsley, whose suggestion that an injunction be taken out to stop Mrs Ebanks from taking office was rejected by council lawyers, said: "We are in uncharted water. No one really knows what is going to happen next."
Mrs Ebanks said she was determined to take her seat as a councillor. "I won fair and square even though they tried to change the system because they didn't want a BNP councillor.
"I am very much a people person and I look forward to helping people at the grass roots in Kingstanding."
Council chief legal officer Mirza Ahmad spent the early hours of yesterday morning consulting London barrister Philip Coppel, one of the country's foremost experts on election law. The advice given was that Mrs Ebanks had been lawfully elected.
Mr Ahmad said: "At this moment in time the individual concerned is duly elected as a member of the city council.
"Election law is defective in a number of respects and the returning officer, even if he realises he has made a mis-take, cannot rectify that mis-take if the candidate has already been declared to have won the seat.
"She is entitled to be sworn in and will no doubt make every effort to do so on Monday. I would have to advise the city council that if we do not swear in the individual concerned we would have to defend litigation from her which I would have to say we are likely to lose."
Sir Albert Bore, the leader of the Labour opposition group on the council, warned that Mrs Ebanks' election would give the BNP an opportunity to gain a foothold in Kingstanding that it did not deserve. She would gain the "trappings of office", which she was not entitled to, he said.
Sir Albert added: "It could take months to take an election petition through the courts and get an annulment of this election result. The Labour group, meanwhile, is in a very difficult position in Kingstanding because we have one councillor duly elected and a second person who was not elected but should, in fact, have been declared the winner."
Simon Darby, regional organiser for the BNP, which picked up nine seats across the West Midlands on Thursday, confirmed that Mrs Ebanks would take the oath of office on Monday. He said the party would resist any attempt to have the result nullified.
The Kingstanding result was the subject of two recounts before Mrs Ebanks was declared the winner.
Mr Darby said: "We won by 300 votes, the result was announced, we celebrated, the police went home and next thing I knew we were being told our votes had been counted twice. How could they count the votes twice?"