A man entered Begum Kulsoom Nawaz's hospital room allegedly without permission at London's Harley Street Clinic on Saturday, sparking alarm among members of the Sharif family.

The wife of the former prime minister Nawaz Sharif has been in critical condition after she suffered a cardiac arrest late on Thursday and was admitted to the ICU and placed on a ventilator.

Begum Kulsoom was diagnosed with lymphoma (throat) cancer in August 2017. She has undergone several sessions of chemotherapy and radiotherapy. Initially, she showed signs of improvement but as of late her condition has deteriorated.

Her sons — Hassan and Hussain — and daughter Asma have remained with her throughout her treatment in London, while Nawaz and Maryam could only visit her a couple of times. Shahbaz Sharif also arrived in London today to see his ailing sister-in-law.

Her son, Hussain, said on Friday that "she is showing some signs of improvement".

The family today was alerted to the presence of an unidentified individual in the hospital room of Begum Kulsoom ─ who, according to Maryam Nawaz, remains unresponsive.

Hussain Nawaz, quoted by Geo TV, said: "This man fooled security and managed to reach Begum Kulsoom's room."

Hussain said he didn't know who the man was, adding: "Even if he is a doctor, it does not mean that he can enter a place he has no concern with."

The former prime minister's son said that the family was already worried, and that this incident had caused further distress to them.

In a video shared on Twitter, the man identified himself as Naveed. He told DawnNewsTV that he is a doctor with a medical practitioner's ID card.

He had allegedly been spotted in the vicinity of the clinic at 9am and went in around 10am when it opened this morning.

Hussain said he had immediately alerted security, who then called the police.

The man, his identity and the circumstances of his entry into the clinic, were inquired into by the police. He was let off with a warning after his medical practitioners' ID card was scrutinised and police did not find him guilty of a criminal offence.

Naveed told DawnNewsTV that he wished to inquire after Begum Kulsoom "in his capacity as a Pakistani".

In the video, upon being questioned, he said: "I went to meet her [...] I haven't done anything wrong."

When questioned about this political affiliation, Naveed said that he was a former member of the Pakistan Tehreek-i-Insaf, reiterating that he was there to "support the Sharif family".

"Every person has links to some party or another," he claimed.

Kulsoom's condition

Speaking to the media outside the hospital, Shahbaz said: "She is still in the ICU. The doctors are trying their hardest to cure her. I request the nation to pray for her health. She is still on the ventilator. They will review it on Monday."

Hussain told reporters that the doctors are not able to provide much information to the family at this time. "An investigation can't be conducted unless there is some stability [in her condition]," he said.

"She is still in intensive care and sedated," he added.

Maryam, in a tweet, said, "The doctors are not saying anything definitively at the moment. They say she's still very critical and under observation."

Begum Kulsoom was pitched by the PML-N in the NA-120 Lahore by-poll after her husband was de-seated following his disqualification as prime minister in the Panama Papers case.

Although she was diagnosed with throat cancer, the party went ahead with her nomination in the by-election that she won in last September. Maryam ran her mother’s campaign successfully in her absence. After the victory, Begum Kulsoom sent a message of thanks to the voters and party workers of the constituency, but was unable to take oath for the seat due to her illness.

After her return from exile along with her family in 2007, Begum Kulsoom preferred to maintain a low profile in politics.

She earned the title of a ‘brave lady’ for her struggle to bail out her husband and in-laws from former military ruler Gen Pervez Musharraf’s captivity following the 1999 coup.