Former Malaysian PM insists he is returning to the political fray ‘with great reluctance’ because he was betrayed by Najib Razak

Mahathir Mohamad is 92 and by his own account should be enjoying a “nice time” during his retirement. But instead, Malaysia’s arch political puppetmaster and former prime minister is returning to the political fray, bent on toppling his former protege and reclaiming power when the country goes to the polls on 9 May.

This time around, the man whose ambitions and political grudges came to influence every major power shift in the country for decades has his sights on bringing down the current prime minister, Najib Razak, a man he dismisses as “corrupt”.

Mahathir insists it is with “great reluctance” that he is running for prime minister again. If he wins, it will make him the oldest leader in the world.

“It’s still quite unexpected,” he tells the Guardian in an interview in his airy office in the administrative capital Putrajaya. “I thought I would retire and have a nice time, but people demanded, kept on asking me to do something. Eventually I’ve had to form a party. I’ve had to be directly involved; I have no choice.”

Mahathir ruled Malaysia with a notoriously iron first from 1981 to 2003, but now gives off the air of a world-weary academic who is allowing himself to be martyred for his cause. “This election is personal. I feel betrayed by him, I can’t help it. Najib cannot separate personal things from political workings,” he says, describing in a tone of great injury how Najib has banned anyone in government from being in contact with him, even those Mahathir has known for years.

This man steals money. Not a few hundred dollars, not a few thousand dollars – he stole billions Mahathir Mohamad

There is a certain irony to his vendetta against the current prime minister. Najib was groomed in office by Mahathir and was once described as his protege. But their allegiance turned to animosity in 2015, when Najib was implicated in the 1MDB scandal, when $2.6bn of a government fund that Najib himself set up went missing and was embezzled around the world. Some $681m of 1MDB money is alleged to have been transferred directly into Najib’s bank account.

While Najib denied the allegations and cleared himself of any wrongdoing, the Malaysian government investigation is widely regarded as a farce, with not a single person arrested. According to Mahathir, the scandal was the moment he realised that Najib was “not the man I thought he was”.

Quick guide 1MDB Show Hide The scandal 1Malaysia Development Berhad, was set up in 2009 to promote economic development. The Malaysian prime minister, Najib Razak, chaired its advisory board and, according to the US Justice Department, top executives and associates of Najib looted $4.5bn from the fund between 2009 and 2014, laundering it through the US, Singapore, Switzerland and other countries. Hundreds of millions landed in Najib's bank account, though he denies any wrongdoing. Where the money went The US Justice Department is seeking to recover money from the fund it says was gambled in Las Vegas, used to buy hotels, apartments, a luxury yacht, a jet, diamond jewellery, art works and to finance Hollywood films including the Wolf of Wall Street and Dumb and Dumber To. The investigation US prosecutors have alleged layers of foreign bank accounts and shell companies were used to launder the money and named Low Taek Jho, a friend of Najib’s stepson, as a key figure in the conspiracy. In one email he wrote "Looks like we may have hit a goldmine" after organising a 1MDB deal that would later allegedly become a money laundering vehicle. Singapore has fined eight banks for failing to carry out proper anti-money laundering measures in relation to 1MDB and given prison sentences to several bankers. Political impact A parliamentary inquiry found many irregularities but had no mandate to prosecute so, outraged by the scandal, 92-year-old former leader Mahathir Mohammad came out of political retirement and opposition united behind him for the elections. The government recently passed a "fake news" law that could be used to further stifle reporting on the case within Malaysia.

“Why do I want to remove Najib? I should have thought the whole world would know,” says Mahathir incredulously. “This man steals money. Not a few hundred dollars, not a few thousand dollars – he stole billions of dollars and that has been verified by investigations here in Malaysia and the US.”

His soft tone becomes suddenly irate. “Najib has made Malaysia among the 10 most corrupt countries in the world and we have evidence to show, evidence that he has covered up under the Official Secrets Act and banned people from talking about [it]. He’s using money to buy up people. He told me himself that ‘cash is king’, told me that [with] that ‘with money I can do whatever I like’.”

Facebook Twitter Pinterest Malaysian prime minister Najib Razak shouts slogans after launching his coalition’s election manifesto ahead of the upcoming polls. Photograph: Mohd Rasfan/AFP/Getty Images

According to Mahathir, there are no villainous depths Najib will not sink to. This week he upped the ante further by accusing Najib’s government of having someone “deliberately tamper with” his airplane, almost preventing him from being able to register as a candidate in the seat he is running for, Langkawi, and therefore stop Mahathir from being able to run as opposition leader.

The animosity and mudslinging exists on both sides. Najib denies all the allegations and a spokesperson from his coalition, Barisan Nasional, told the Guardian Mahathir’s “22-year self-confessed dictatorship has been a series of evasions, outright lies and claims of memory loss”.

Certainly Mahathir’s administration had its own scandals, both in its tendency to award multibillion-dollar government contracts to the prime minister’s allies, but also for financial mismanagement. In a book about Mahathir, the Wall Street Journal’s Barry Wain claimed that 100 billion ringgit went missing under his watch. “There was corruption that happened when I was prime minister but not on this scale,” says Mahathir.

An unlikely alliance

So determined is he to remove Najib from office that Mahathir formed his own political party last year and swapped sides – he and Najib were both part of the Unmo party. Mahathir formed an alliance with the opposition coalition, now running as the leader of the very set of parties he tried to destroy as prime minister.

He firmly believes that as the one who “made” Najib, he is also the only one who can take him down. Certainly the opposition, which has never won an election, is stronger and more united under his leadership than ever before. The “Mahathir factor” has also made the election outcome more uncertain than originally predicted - 65% of the seats are now competitive compared with 50% in 2013, despite Najib’s government doing everything possible to swing the system in its favour.

“These people who described me as a dictator, throwing people in jail, now they are asking me to lead them,” Mahathir says with a laugh. “I never really thought the opposition would accept me, and I didn’t really think I would accept them. But we were all very much against Najib and they consider that more important than any differences we had before. So now I am with them and they are with me.”

Yet the political melodrama doesn’t end there. Part of Mahathir’s deal with the opposition coalition is that, should he win them the election, he will quickly cede power to Anwar Ibrahim. Anwar was another of Mahathir’s former proteges, but whose path to the top was halted in 1999 when he was perceived as getting too powerful. Mahathir had Anwar jailed for sodomy, a crime in Malaysia. He has always stood by the decision: in 2005, when it looked like Anwar’s career was to be revived, Mahathir was recorded at a human rights conference saying: “Imagine a gay PM ... Nobody will be safe.”

Malaysia needs democracy. I’m in prison for that belief – but I won’t change it | Anwar Ibrahim Read more

But times have changed. With Anwar due to be released from jail in June (he is currently serving a second sentence for sodomy), the plan, consented to by Anwar from behind bars, is for Mahathir to have him pardoned and make way for him to become the country’s eighth prime minister, if you count Mahathir twice. “I don’t call it a sacrifice, I think it’s just a necessary thing I have to do,” says Mahathir on this unexpected alliance. But does he still believe Anwar is gay? “Well that is what the police told me,” he says, skirting the question. “I didn’t examine him, but I am dependent on the police and I have to accept their evidence.”

On the question of whether Anwar deserves to be locked up for being gay, Mahathir is more forthright. “I’m a Muslim, we don’t accept that,” he says. “You can be a liberal and accept same-sex marriage and all that, but that’s your business. We are very orthodox people.”

The opposition coalition has stated that Mahathir will remain in office for a maximum of two years before Anwar takes over, but Mahathir clearly views the timetable as a little more flexible. After all, he says, “it won’t take too much time to pardon Anwar, but I need to have time in office – two years, three years – because there are things that I need to do, which my experience will help”.

If he wins power, the first thing Mahathir will do, he says, is reclaim the stolen money, much of which is still in the US, Singapore and Switzerland, and jail anyone found to be implicated in 1MDB. And he is not averse to prosecuting Najib.

They come to my rallies in their thousands ... If I had been an authoritarian dictator, this would not happen Mahathir Mohamad

“If we find he has broken the law and stolen money, as the evidence shows then, yes, we will make sure he faces charges in court,” says Mahathir. “If Najib is found guilty, then of course due process will be carried out.”

He also intends to “restore the rule of law”, which, he says, has been dismantled under Najib. Yet Mahathir himself was not known to have great respect for the rule of law. In 1988, after an adverse ruling, he fired the chief justice and two other senior judges. He also locked up political opponents, banned public protests and unapologetically stifled criticism with a barrage of repressive laws.

Yet Mahathir now takes umbrage at the suggestion he was an authoritarian leader. “ I resigned on my own and during my time the country enjoyed a period of great prosperity,” he says. “And now [I am] going round the country and no one tries to stop me or bash me on the head. They come to my rallies in their thousands, shouting their support. If I had been an authoritarian dictator, this would not happen.”

Perhaps then, has he softened in his older years? After all, he has had two heart bypass surgeries and was recently in hospital for an issue with his lungs (the ruling coalition are terrified he will not make it through the election and that his death would somehow be blamed on them). He is steely in his answer. “Do I look like a senile old man to you?” he asks with small smile. “No, I thought not.”