Former deputy prime minister Lu Lay Sreng was given the green light to return home after Hun Sen said he would not face arrest over his court cases for defamation and insulting King Norodom Sihamoni.

However, the prime minister said his mercy was only for Lay Sreng, speaking of his anger with a “group” for questioning the legitimacy of one of his children, saying he would “smash” them as he had Khmer Rouge leader Pol Pot.

Speaking to The Post on Monday, Lay Sreng said: “I thank Samdech [Hun Sen] for allowing me to return because living abroad is difficult and I am homesick to death."

“But before I return, I need to see my doctor as my health requires me to have a medical check-up once a month . . . because I have a heart problem, had a stroke and suffer brain problems."

“But now I feel relieved that [Hun Sen] has allowed me to go back – I feel like my ailments are cured,” the 80-year-old Lay Sreng said, adding that he has been living in Thailand with two grandchildren.

He took to Facebook on Monday to thank Hun Sen, promising to never commit such wrongdoings again.

“I will not dare talk about the King because doing so made me have to flee Cambodia, and it affected the King’s dignity. Again, I would like the King to pardon me, as someone who served the country when King Father [Norodom Sihanouk was on the throne] and under the current King,” he said.

At a graduation ceremony for more than 3,000 Vanda Institute students on Monday, Hun Sen said he would allow Lay Sreng to return home without facing arrest.

“Come on grandfather, no one will arrest you! I don’t need to write a letter requesting a pardon for you. You made a request and I am replying."

“Now the door is open for Lay Sreng to return. I beckon you and say: ‘Grandfather, come back.’ But don’t be silly anymore. Don’t [insult] the King,” Hun Sen said.

Hun Sen said he had told the minister of justice to review the case and find a way to annul the compensation demanded of Lay Sreng by requesting a pardon from the King.

But he said Lay Sreng could return “even today” before the pardon letter was issued. The prime minister said he would have a meal with him when he returned.

Political analyst Lao Mong Hay said Lay Sreng’s transgression was minor. He said a reasonable person would not feel as hurt by remarks made in a private conversation than by those aired in public.

Lay Sreng was charged with defamation by Phnom Penh Municipal Court for claiming in a recorded phone call that Hun Sen had given $1 million to the royalist Funcinpec party to take the National Assembly seats of the former opposition Cambodia National Rescue Party (CNRP) after its dissolution by the Supreme Court in November 2017.

He also accused Funcinpec members of bribing the leader of the party with $20,000 each to get the seats inparliament.

Lay Sreng also faced another charge of insulting King Sihamoni.

All three charges stemmed from a private phone conversation with a former colleague that was recorded and leaked on social media.

In early 2018, the Phnom Penh Municipal Court found Lay Sreng guilty of defamation and ordered him to pay Hun Sen 500 million riel (around $125,000) in compensation.

Hun Sen continued, speaking of his anger at a group of people who alleged that his son Hun Manet was the son of first lady Bun Rany and a Vietnamese leader. He said they would never be forgiven, and he would destroy them like he did Pol Pot.

“There is an insult for which I will never forgive this group of dogs. What was it? They said my wife was the lover of a Vietnamese leader and Hun Manet is his son. For this, you need to remember, I will never forgive you in my whole life,” he said.

“I sent video clips [regarding the accusation] to foreign embassies. For this, I won’t forgive you. Don’t say I take a personal matter over big issues. You can do this to me, but I won’t forgive you. I mark a target to smash you like I marked a target to smash Pol Pot. You remember this,” he said.

Even though he did not name those in question, Hun Sen may have been referring to people connected with his long-time political rival Sam Rainsy.

In 2016, a member of the CNRP, Yorng Noy, also known as Brady Young, was kicked out of the party for making the allegation.

Rainsy condemned the claim and wrote a letter to Hun Sen offering his sympathy.

The “acting president” of the CNRP on Monday said he did not pay attention to the private affairs of other people.

“Hun Sen is an irresponsible leader who wants to divert public attention away from national issues he cannot solve with his private affairs, about which he makes silly accusations against other people."

“He uses such accusations as a pretext to crack down on his political opponents,” he said via email.

Political analyst Lao Mong Hay said it was understandable for a father to be hurt if it was said in public that his child had been sired by another man.

“These people deserve this kind of treatment from the prime minister. But a great statesman with strong self-confidence would take the moral high ground and ignore them however hurtful their comments might be,” he said.