PML-N Vice-President Maryam Nawaz on Friday dismissed allegations by former premier Imran Khan that a "foreign conspiracy" was hatched to topple his government, saying the letter the PTI chief had been referring to as evidence "does not even exist".

Addressing a public gathering in Fateh Jang, Attock, Maryam said Imran had "lost his mental balance" after losing power in the wake of the no-confidence motion.

She accused the ex-premier of "repeatedly changing his narrative" about the conspiracy, saying "first he asserted that the letter was received in March and just a day ago he disclosed that he was aware of the plot since July [last year]".

Maryam questioned Imran for raising hue and cry on his exit, reminding him of his previous statements wherein he had said he was happy that the opposition submitted the no-trust motion against him. "Now that the no-trust motion has succeeded, people must ask Imran why is he raising objections?"

Imran, who was ousted on April 10 through a no-confidence motion moved by the joint opposition, stirred a controversy two weeks before his ouster when, at a rally, he had brandished a letter, claiming it contained evidence of a "foreign conspiracy" hatched to topple his government.

Imran's allegation that the US spearheaded his exit from power was based on a cable received from Pakistan's Ambassador to the US, Asad Majeed, in which the envoy had reported about a meeting with Assistant Secretary of State for South and Central Asia Affairs Donald Lu.

The Pentagon and the State Department have repeatedly rejected the accusations, saying there was no veracity to it.

Later, the National Security Committee (NSC), which includes all services chiefs as well as the head of Pakistan's top intelligence agency, held two meetings to discuss the matter.

The first meeting on March 31, chaired by then premier Imran Khan, had decided to issue a "strong demarche" to a country that it did not name over what it termed as “blatant interference in the internal affairs of Pakistan”. It had also termed the interference "unacceptable under any circumstances" and said the language used in the communique was undiplomatic.

While the forum had stopped short of calling the interference a conspiracy at the time, another meeting of the NSC was held on April 22 with newly elected premier Shehbaz Sharif in the chair, and which included the same military chiefs who attended the March 31 session.

After its second meeting, the NSC statement said it “discussed the telegram received from Pakistan's former ambassador to the US" and "reaffirmed the decisions of the last NSC meeting" but went on to add that it found no evidence of a foreign conspiracy.

At the rally today, Maryam said Imran's government was supported by "crutches" which were destined to collapse.

The PML-N leader hit out at the ex-PM for his plan to march towards Islamabad, saying Imran's actual aim was to save Farah Khan — a close friend of his wife Bushra Bibi — against whom the National Accountability Bureau has begun an 'assets beyond means' inquiry.

"As soon as Imran realised the impending success of the no-trust motion, he paved the way for Farah to leave the country within a day."

She asked why Farah left the country if her real estate business was thriving and flourishing in the country, as Imran had claimed. She hinted that Interior Minister Rana Sanaullah would take measures to bring the woman to the country to face corruption charges.

PML-N has been accusing Imran and the PTI government of using Farah as their "frontperson" to secure bribes in different projects on behalf of the ruling elite.

Maryam also alleged that Imran was more annoyed at Shehbaz becoming the prime minister than his own ouster.