After almost a year of constant attacks against the leadership of Prime Minister Najib Abdul Razak, Dr Mahathir Mohamad reiterated today that there would be no let-up by him in efforts to unseat the current PM.

"Well, I always believe that when you fail, you get up and try again and again. It's whether that what we have been doing is worthwhile or not," the nation's longest-serving premier of 22 years said.

He was speaking to reporters after launching the 'My New Proton' initiative in Shah Alam today.