The Pakistan Muslim League (Nawaz) (PML-N) chief felt pain in the chest yesterday morning and was taken to Central London hospital for a check up, where doctors decided to keep him for further observation, party sources said.
The 64-year-old Sahrif has been in the British capital for the past few days after arriving from Lahore via Switzerland on a private visit.
Meanwhile, his younger brother Punjab Chief Minister Shahbaz Sharif has also reached London on hearing about the medical problem of his brother.