Johannesburg - Botswanan former president Ian Khama has accused his chosen successor of becoming an autocrat and threatening the country's reputation as a beacon of stability in Africa.
Khama, 66, last week left the ruling Botswana Democratic Party (BDP) in a culmination of a dramatic fall-out with President Mokgweetsi Masisi, who took office last year.
Khama told AFP that he took the "very painful" decision to leave the BDP because of the "immature and arrogant" attitude of Masisi's government.
"The person who I nominated to be my successor, as soon as he took office became very autocratic, very intolerant and it has led to a decline in the democratic credentials that we have a reputation for," Khama said in a telephone interview.
After serving the constitutional maximum of ten years in office, Khama handed power in April 2018 to Masisi, who was then his deputy.
Khama stepped down 18 months before elections, allowing Masisi to settle into the role and start campaigning.
But the two leaders have clashed so badly that Khama last weekend quit the party and declared he would campaign against it in the October elections.
Khama - whose father Sir Seretse Khama co-founded the BDP in 1962 - said he was not joining another party but would back some opposition parliamentary candidates.
He said some senior BDP officials fear the party may be "heading for an election defeat" because they believe Masisi "has now become a liability".
Since coming to office, Masisi changed several key policies adopted by Khama -- the most high-profile being the lifting of the wildlife sports hunting ban imposed in 2014.
"To me it's so sad and extremely painful that all these years' work to build up to what we had achieved is being put in reverse," said Khama, adding Masisi never previously objected to the ban.
"We have had stability for many years, we have had wildlife for many years, we have been trying to play our part as a responsible member of the international community in fostering democracy.
"When you see what is happening, putting all the hard work into reverse, it is unacceptable."
Khama accused Masisi of cracking down on dissent in Botswana.
"Anybody who is seen as an opponent in the party or opposition parties -- there is this use of state security organs to go after them and harass people," he said.
"Those are things we have never seen in Botswana and one just cringes. It's that bad."
"I have seen that happen in other countries," he added, warning the country would "gradually start having a serious deficit in democracy."
Masisi and the BDP have not publicly responded to Khama's criticisms.
"It was a very painful decision, a very hard one and I gave a lot of thought to it," the former leader said about leaving the party, which has ruled Botswana since independence from Britain in 1966 but lost popularity under Khama's rule.
When in office, Khama was renowned for his straight talking - publicly criticising US President Donald Trump and then-president Robert Mugabe in neighbouring Zimbabwe.
He said he was determined to be equally frank about Masisi.
"When he was my vice president... he never displayed any of these issues we are now seeing, (he was) always very intelligent, very supportive of all these policies that he is now reversing."
Botswana last week attracted world headlines over Masisi's decision to end the hunting ban.
The government said elephant hunting would help control the booming population which it said was causing serious damage to farmers' livelihoods.
Botswana has the world's largest elephant population with more than 135 000 roaming freely in its unfenced parks and wide open spaces.