In a blow to the incumbent government, which had placed a condition of indemnity bonds for Sharif's travel, the court on Saturday ordered it to remove his name from the Exit Control List (ECL) without any conditions, Dawn news reported.
In a statement, Pakistan Muslim League-Nawaz spokesperson Marriyum Aurangzeb said that the process of administering a high dose of steroids to Sharif was underway so that his platelet count could be brought to a suitable level for travel.
He was also being given medication to lower his high blood sugar and other medical issues, she said.
Earlier on Sunday morning, the former premier's personal physician, Adnan Khan, said that Sharif was scheduled to travel to London within 48 hours "once he's clinically stabilised, made travel-worthy (and) is safe for air travel".
"He will make the journey in a fully equipped (and) medically staffed air ambulance; arriving soon," Khan added in a tweet.
PML-N President Shehbaz Sharif hailed the decision and signed an undertaking which stated that he would "ensure return" of his brother "within four weeks or on certification by doctors that he has regained his health and is fit to return back to Pakistan".
On November 13, the Pakistan Tehreek-i-Insaf (PTI) government, after much deliberation, had granted a one-time permission to Nawaz Sharif for four weeks to travel abroad for his treatment provided he submitted indemnity bonds worth over 7 billion Pakistani rupees.
The condition was challenged in the Lahore High Court by the PML-N legal team the next day.
( With inputs from IANS )