Former Birmingham City Council chief executive Lin Homer may have to return to court to defend herself against allegations that the 2004 local authority elections were marred by widespread postal vote fraud.

Five former Labour city councillors have applied to the Court of Appeal for judicial reviews after being found guilty earlier this year of ballot-rigging in Aston and Bordesley Green.

They were said by an elections court judge to have been part of a systematic city-wide attempt by Labour to retain control of the council through the use of bogus postal votes.

Council lawyers fear that fresh hearings could re-open allegations that Ms Homer, as Returning Officer, operated "lax procedures" at the election count by allowing fraudulent votes to stand. The claims have already been rejected by the elections court.

A sixth former Labour councillor, Mohammad Afzal, was also found guilty of corruption but cleared on appeal. His case may be the subject of a further appeal to the House of Lords.

New evidence centred on 275 completed but uncounted postal votes found in the council offices months after the June 2004 polls could be introduced in the judicial review process.

The council, which has already spent £300,000 on legal costs connected with the Aston and Bordesley Green election trials, has agreed to indemnify Mrs Homer against costs arising from any future court hearings.

A report by council chief legal officer Mirza Ahmad estimated that the bill to cover Mrs Homer's additional court appearances could amount to £30,000.

The report added: "The former Returning Officer wishes to keep her involvement in the appeals to a minimum although the Court of Appeal may take the view that due to the complexities of the appeals the former Returning Officer needs to participate."

Mrs Homer stood down as council chief executive at the end of July to take up a new position as head of asylum seeker policy at the Home Office.