Prime Minister Najib Abdul Razak today expressed confidence in the loyalty of his deputy Ahmad Zahid Hamidi despite former prime minister Dr Mahathir Mohamad's attempts to cast doubts.

Najib said he believed Zahid will not go back to Mahathir after what the latter did to Zahid when he was prime minister.

Najib referred to Mahathir's detention of Zahid under the Internal Security Act (ISA), which he likened to putting a "pistol to his head".

"He (Mahathir) used his full power (against Zahid), like putting a pistol to his head.

"That is why Zahid does not forget. That is why it does not make sense for the deputy prime minister to meet Mahathir and ask for his support.

"It is impossible and false, it is a slander," Najib told delegates when officiating the Shah Alam Umno division delegates' meeting in Shah Alam today.

Mahathir in a blog posting alleged Zahid had sought for his support in replacing Najib as prime minister.

Brushing aside the claim, Najib went on to speak about his long relationship with Zahid.

"Now he (Mahathir) wants to pit me against Zahid. He doesn't understand that Zahid and I go way back to 1986, we went through thick and thin together.

"I defended Zahid in Bagan Datoh (during the party election) against the then Umno division leader, in the end, he (Zahid) won with 11 votes.

"I defended Zahid since the start because he was my friend... I knew about his misery.

"Zahid was Umno Youth chief in 1998 but he was placed under the ISA. Can you imagine if I were to put the Umno Youth chief under the ISA?" he said.

Zahid had courted Mahathir's wrath after he backed the then prime minister's rival Anwar Ibrahim, who was sacked as deputy prime minister.

However, Zahid later renounced Anwar and was accepted by Mahathir.

'Zahid forced to resign'

Najib claimed during the fallout with Mahathir, two Special Branch officers were sent to Zahid, asking that he sign a letter of resignation as Umno Youth chief if he wanted an early release from detention.

"As brave as he was, he still thought about his wife and children at home and, in the end, he signed the letter.

"But the officers came again the next day and asked him to sign another letter stating that he did so willingly. What does this mean?"

Meanwhile, Najib, earlier in his speech said that he and Mahathir may not see eye to eye but that does not mean that the latter could go to the extent of "betraying Umno".

"Difference in opinion is normal, but if we look back at history, no one was spared.

"He even bad mouthed (former prime minister) Hussein Onn who appointed him (as prime minister). He fought with Tengku Razaleigh (Hamzah), Musa (Hitam), Anwar (Ibrahim), Abdullah (Ahmad Badawi).

"He didn't have the opportunity to fight with only Abdul Razak (Hussein), so he waited for his son (Najib)," said Najib.

Najib said it did not make sense for all these personalities to be in the wrong, as claimed by Mahathir.

He also reminded Mahathir how the latter too had faced criticism when he was prime minister, being branded with names such as "Mahazalim", "Mahafiraun" and "Mamak Bendahara" by his opponents.

"But now he is together with the opposition. PKR was born because of Mahathir," he said.

Najib also trained his guns at the opposition for failing to name a prime minister candidate.

"As long as the opposition does not decide on its prime minister candidate, it has no credibility," he said.

'Dr M-Zahid meet was recorded'

Zahid had denied trying to undermine Najib and claimed his meeting with Mahathir was with the prime minister's permission.

Zahid also claimed that both Mahathir and he have a recording of the meeting which took place in 2015.

Meanwhile, DAP parliamentary leader Lim Kit Siang said the recording should be made public to clear the air on the matter.

"Zahid has said right from the beginning that he has the recording of the meeting between him and Mahathir in 2015. In fact, he said Mahathir also has a copy of the same recording of the meeting that was held by them in 2015.

"If so, why the tape recording of the Mahathir-Zahid meeting in 2015 has yet to be played for everybody to know what actually transpired if it is true that both Zahid and Mahathir have a tape recording of their meeting in 2015?" he said.