Former prime minister Dr Mahathir Mohamad has made a lot of critical views about loyalty and corruption in his campaign against Prime Minister Najib Abdul Razak.

For many, it's a big shift from the Mahathir of the 1980s and 90s, who himself was accused of corruption and cultivating a culture of cronyism.

Malaysiakini takes observations made by former deputy prime minister Musa Hitam, in his book 'Frankly Speaking', and compares these with statements Mahathir had made recently, to see how much the 91-year-old has changed his views, at least in public.

Mahathir's views on loyalty then:

"As prime minister, Mahathir demanded absolute loyalty. Moreover it was loyalty of a personal nature and not at all like the loyalty I believed in. I saw loyalty as being specific to the party, to the position, to the nation, and ultimately, to the rakyat.

"Dr Mahathir demanded absolute loyalty, insisting that it was the price of good government. He expected one to stay loyal to him, even if he himself acted wrongly. And if his loyal supporters acted wrongly, they would also be forgiven and protected.

"With Mahathir, loyalty was an obsession - loyalty over performance, loyalty over ability, and loyalty to him as party chief." - Musa Hitam, Frankly Speaking

Mahathir's views on loyalty now:

"Today, most Umno leaders and members have become dumb, deaf and blind. They know Najib's faults but still support him. Whatever wrongs Najib has done, they still support (him)." - Mahathir's blog

"The Malays now don't weigh their own beliefs... They tie themselves to the party. Even if the party does a huge wrong they will continue supporting the party." - Mahathir's press conference in Sungai Besar

Mahathir's views on corruption then:

"I learned that when the ACA (Anti-Corruption Agency) investigated an individual, there were times when no decision was taken. Sometimes the prime minister (Mahathir) would show no interest in a particular case. At other times, investigations would be followed by a more serious course of action, namely prosecution.

"As a result of my discussions with Dr Mahathir on those matters, I sensed that he believed that, when in a position of authority, one had to practise discernment and steer a course that was balanced between political expediency and good governance. In other words, the wider political ramifications had to be considered." - Musa Hitam, Frankly Speaking

Mahathir's views on corruption now:

"I hope the people will not accept corruption because it is haram, and it can destroy the country." - Mahathir's speech in Kedah

"Those who are trying to legitimise corruption remain as one of those criminals who have sinned. Even worse are those who know that religion prohibits corruption but nonetheless they try to legitimise corruption. Their sins would certainly multiply if because of their claim that corruption is lawful, others will accept bribes." - Mahathir's blog

These comparisons have often been drawn by other critics of Mahathir from Umno, such as Tourism and Culture Minister Nazri Abdul Aziz.

Even Najib recently reminded Mahathir of the corruption allegations against Mahathir himself, and that the former PM was once called "the head of thieves".

On a less serious note, Musa in his book also revealed a few things that most people may not have known about Mahathir.

Mahathir's cabinet nicknamed him 'Tok Bomoh'

Musa described Mahathir as a belligerent and contemptuous individual, who liked to poke fun at people and come up with rude nicknames.

"For example, he nicknamed one cabinet minister Mat Bulat (Round - i.e., fat - Mohamed). It was an unfair name which showed everyone that the minister was not liked by the prime minister.

"In fact, I am quite certain that he created rude nicknames for each of us in cabinet. Some of us decided to get even. We therefore gave him the nickname 'tok bomoh' (medicine man)," Musa said, without properly explaining the reason behind that nickname.

Mahathir took singing lessons

Musa said that back in the day, companies and individuals would offer to donate large sums of money to charity if Mahathir, Tengku Razaleigh Hamzah and himself would sing individually at public functions.

"I was told that I was quite good at singing. So was Razaleigh. Dr Mahathir, on the other hand, was not a good singer.

"As an excuse for his poor singing, he used to joke that he couldn't perform well because I would already have spoiled things... 'Trouble is,' he would say, 'Musa's voice would come into my mind'," the former deputy prime minister says in his book.

Nevertheless, Musa noted, Mahathir eventually became "quite a singer" after taking singing lessons with the same determination he put into politics.

Mahathir wanted to invent an Islamic toilet

Mahathir also had an innovative and creative side, according to Musa, and wanted to invent an "Islamic toilet" to improve public hygiene, and even made a prototype he asked the cabinet to inspect.

Mahathir was quite defensive about the project and took offence when Musa shared with him the designs of a high-tech toilet he had used while in Switzerland. He reportedly said: "Musa has just told me that my toilet is not good enough, and he's brought a Swiss alternative."

Musa doesn't say what an Islamic toilet is, but by his descriptions of the Swiss toilet, it appears to be an automated type of toilet which includes a bidet to do all the cleaning, hands-free.