The by-election is a four-way contest between Dr Wan Azizah Wan Ismail (PKR), Suhaimi Sabudin (BN), Azman Shah Othman (PRM) and Salleh Isahak (Independent).
10.18pm: OFFICIAL RESULTS FROM ELECTION COMMISSION
PKR - 30,316 (57.1% of the popular vote, down by 1.47%)
BN - 21,475 (40.44% of the popular vote, up by 0.38%)
Independent - 367
PRM - 101
Spoilt vote: 843
Quick analysis: Although the majority down by 2,880 votes due to a lower turnout (74.53 percent turnout, compared to 88.3 percent in 2013), the share of the popular vote dropped by 1.47 percent.
In contrast, BN's share of the popular vote in the Rompin by-election two days ago dropped by five percent from 65.52 percent to 60.57 percent.
9.31pm: Latest unofficial results with more or less all votes counted.
PKR - 30,504
BN - 20,586
Ind - 359
PRM - 98
Majority - 9,918
8.30pm: Latest unofficial results. BN breaches 20,000 mark. One more polling district to go.
PKR - 29,561
BN - 20,019
Ind - 350
PRM - 96
Majority - 9,542
Quick analysis: The present set of figures suggests that PKR's share of the popular vote remains the same as the general election in 2013.
Now given the fact that there was a lower turnout, it would be reasonable to suggest that PKR would have won with a bigger majority if the turnout was higher.
The turnout in this by-election is about 15 percent lower than at the 2013 general election (88.3 percent in 2013, about 73 percent in today's polls).
With 95 percent of the votes counted, PKR is looking at a majority of lower than 10,000, down from the 11,721 it garnered two years ago at the 13th general election.
Alhamdulillah pengundi Permatang Pauh kekal sokong kuat KEADILAN dan tolak GST. Trend sokongan pengundi muda meningkat dengan besar.
— Mohamed Azmin Ali (@AzminAli) May 7, 2015
8.15pm: About 90 percent of the votes has been counted thus far and PKR's majority is still widening.
PKR - 27,971
BN - 18,633
Ind - 342
PRM - 98
Majority - 9,338
Quick analysis: Although BN made marginal gains of between one to three percent in several polling districts where PKR won, it lost Kampung Belah Dua to PKR this time round.
BN won 51.6 percent of votes in Kampung Belah Dua in the general election last year, but only managed to garner 49.3 percent of the votes this time.
It was one of only six polling districts it won in Permatang Pauh in 2013. There are a total of 28 polling districts in the parliamentary constituency.
8.05pm: By securing more than 26,000 votes, PKR has secured Permatang Pauh in view of the fact that about 52,000 people voted.
Thus far, 85 percent of the votes have been counted.
PKR - 26,631
BN - 17,939
Independent - 328
PRM - 96
Majority - 8,692
7.55pm: Latest unofficial count:
PKR - 23,745
BN - 16,497
Independent - 269
PRM - 95
Majority - 7,248
Quick analysis: According to this breakdown, it would mean that PKR's share of the popular vote is 58.5 percent, slightly lower that 59.2 percent achieved in the 2013 general election.
7.50pm: Quick analysis: swing to BN or PKR is between 0.1% and 3% at various district polling centres. Though BN may have a slight edge. It appears that the main factor affecting the final majority will be the turnout as the swings are marginal.
7.40pm: PKR continues to extend its lead over BN.
PKR - 20,727
BN - 14,034
Independent - 244
PRM - 89
Majority - 6,693
7.35pm: Quick analysis of four voting districts:
- Mengkuang (91.8% Malay) = +0.1% swing to PKR
- Sungai Semambu (71% Malay, 21% Chinese) = +0.04% swing to PKR
- Sungai Lembu (98.7% Chinese) = +13.8% swing to BN
- Telok Wang (58.1% Malay, 26.7% Chinese) = +3.3% swing to BN
Note: BN only won 16 percent of the votes in Sungai Lembu in 2013. However, BN won 30.4 percent this time round and this is cause for MCA and Gerakan to celebrate.
Preliminary result in Permatang Pauh shows significant increase support of Chinese community to BN compared last GE. Notable at Sungai Lembu
— Tan Keng Liang (@tankengliang) May 7, 2015
7.26pm: The majority for PKR is still growing. It is safe to conclude that the independent and PRM candidates will lose their deposit.
PKR - 16,009
BN - 10,588
Ind - 173
PRM - 62
Majority - 5,421
7.20pm: At this point, PKR seems to be on track to maintain its 59.2 percent share of the popular vote similar to the general election in 2013.
Latest unofficial count:
PKR - 14,958
BN - 9,793
Ind - 163
PRM - 60
Majority - 5,165
7.15pm: According to unofficial sources, about half of the votes have been counted and the results are as follows:
PKR - 14,504
BN - 9,550
Ind - 163
PRM - 60
Majority - 5,027
7.10PM: PKR leads with 12,008 votes, BN 7,863 and the majority now stands at 4,145 .
7.08pm:As of 7pm, PKR is leading the contest with 8,452 votes, BN 5,380, majority 3,072.
Reporting by Alyaa Azhar, Low Chia Ming, Nigel Aw, Susan Loone and Zulaikha Zulkifli.