Pakatan Harapan is unperturbed by Umno and PAS formalising their ties, Dr Mahathir Mohamad said today.

Writing in his blog Chedet.cc, the Harapan chairperson said the union provides a chance to raise many issues and expose the "lies" told by both parties.

Mahathir cited as an example PAS' purported pledge last month to back him in the case of a no-confidence vote in Parliament.

"PAS leaders then said they would not campaign for BN in Semenyih. But on nomination day, many PAS leaders appeared with their BN counterparts.

"Is this PAS' promise?" he asked.

After a Feb 15 meeting with PAS leaders, Mahathir claimed he was handed a written agreement stating that the party would not support BN in the Semenyih polls.

However, PAS secretary-general Takiyuddin Hassan later said that the agreement was actually a draft pledge to back Mahathir with the support of its 18 MPs if Harapan initiated a no-confidence vote against him.

Harapan leaders have denied the existence of any such move.

'Slave to Bossku'

Mahathir also claimed that the formalisation of ties between Umno and PAS seems more like an attempt to return former premier Najib Abdul Razak to power and "cleanse" him of his alleged crimes.

"Does PAS consider Najib, who is facing charges of graft and abuse of power, innocent?

"Can corruption, abuse of power and crime be considered halal in the name of Malay-Muslim unity?" he asked in his blog post.

Mahathir also stressed that PAS should look at the fact that Umno lawmakers are abandoning the party before taking their political cooperation any further.

The Islamist party, he added, should also be cognisant of the image it is projecting by working with Umno and Najib – better known, of late, by his social media moniker 'Bossku.' 

"Boss means 'master to slave'. Is PAS willing to become a slave to a suspected thief? 

"Has PAS no shame for accepting Najib as their 'boss?'"