PENANG, Malaysia (BBC) -- A special election in the Malaysian state of Penang is likely to see opposition leader Anwar Ibrahim returned to parliament.

The 61-year-old is favorite to win Tuesday's vote in what will be a highly symbolic return to national politics.
The campaign has been dominated by renewed allegations that Anwar committed sex abuse -- charges he has rejected as a smear campaign.
Just a single seat is at stake but the event has transfixed Malaysians.
Millions have been spent, the day-to-day business of government is on hold, thousands of supporters have flooded into the small area of Permatang Pauh to try to help or hinder Anwar, and there is a heavy police presence in Penang.
-------------------------- Titanic struggle
The man who led Malaysia's new opposition coalition to an unprecedented showing in a general election earlier this year is now on the brink of winning a seat in parliament himself -- a crucial springboard in his bid to bring down the government.
""The Malaysians consider this a critical point in our history, whether we get the mandate to chart a new course for Malaysia or we should just be happy with the same corrupt establishment,"" said Anwar.
He is almost certain to win the contest but nonetheless the effort against him is immense.
Deputy Prime Minister Najib Razak is leading the campaign on the other side. He told the BBC this was a ""titanic struggle"".
One senior government politician even described it as a ""jihad"".
The government-controlled newspapers have lead the assault on Anwar, emphasizing the sex abuse allegations.
Voting irregularities have been uncovered.
Unknown government supporters have also put up several Israeli flags -- a very rare sight here -- in an attempt to persuade the mainly Muslim voters that the opposition leader is sympathetic to the Zionist state.