Umno and BN will be defeated in the next general election unless Prime Minister Najib Abdul Razak steps down, said Dr Mahathir Mohamad.

The former premier unleashed his most vitriolic attack on Najib on the eve of the prime minister's sixth year in office.

In a blog post today, Mahathir said his prediction was based on the fact that Najib has not been able to answer a slew of allegations against him.

"The people - be it Malays, Chinese, Indians and ethnic groups from Sabah and Sarawak - don't trust Najib.

"Umno members and their leaders must wake up to the fact that Umno and BN will lose if Najib leads Umno until GE14.

"When Umno loses, the Malays will criticise the party's leadership, which is so weak that it is now rejected by the Malays.

"Once Umno loses, it will not recover," he warned.

'I'm not senile'

Among others, Mahathir cited the mystery surrounding the motive behind the murder of Altantuya Shariibuu , whom he said was involved in the "scandal" surrounding the purchase of two naval submarines.

He also attacked Najib over his handling of the 1Malaysia Development Bhd (1MDB) controversy, his links to tycoon Jho Low, his stepson Riza Aziz's fortune and the purchase of a new luxury jet.

"Apart from these allegations, the Najib administration's policies is limited to doling out cash (and) irking Malays by dropping the New Economic Policy to gain Chinese support.

"Nevertheless, the rejection of BN during GE13 had already proven that the Chinese reject his leadership," he added.

As a parting shot, Mahathir said he was "not senile" despite being almost 90.

"Those who say I'm senile are lying to themselves," he added.

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