His younger brother Punjab Chief Minister Shahbaz Sharif saw him off at Lahore airport. Before leaving for London, Mr Sharif asked the people to pray for the health of his wife who is suffering from throat cancer.
According to Mr Sharif's close aide Senator Pervaiz Rashid, the former premier will stay in London for at least 10 days. "However, he may extend his stay for more days depending on Begum Kulsoom's health," he said.
Mr Sharif's exit from Pakistan came amid rumours that he may not return to the country as he is facing corruption and money laundering cases. The country's National Accountability Bureau (NAB) is going to file four cases against Mr Sharif and his children.
Mr Rashid, however, dismissed the rumours, saying Mr Sharif loves his country. "Why would Sharif choose to stay away from the country where he is loved the most by the people? The circumstances today are not the way they were in 2007, when dictator Musharraf was ruling here. Even at that time, Sharif had returned to the country from exile (in Saudi Arabia) but he was sent back by the dictator," said Mr Rashid.
Begum Kulsoom has been receiving treatment for throat cancer (lymphoma) in London.
Mr Sharif's sons - Hussain and Hasan - and daughter Asma are already with Ms Kulsoom in London. However, his daughter Maryam who is active in politics and is tipped as his successor and future prime minister candidate is not going to London as she has to run campaign in Lahore.
The seat fell vacant after Supreme Court disqualified Nawaz Sharif in Panama Papers case on July 28.