(Reuters) - Pakistan's three-time Prime Minister Nawaz Sharif arrived home on Saturday from four years of self-imposed exile in London to kick start his party's campaign three months before a general election, local television reported.

The 73-year-old veteran politician will lead a rally in his eastern hometown of Lahore after his chartered plane's arrival in Islamabad with 194 people from his party and media organisations, the party and sources said.

Sharif had not set foot in Pakistan since he left for London in 2019 to receive medical treatment while serving a 14-year prison sentence for corruption. His convictions are still in force, but a court on Thursday barred authorities from arresting him until Tuesday, when he is to appear in court.

While he cannot run again for election or hold public office because of his convictions, his legal team says he plans to appeal and his party says he aims to become prime minister for a fourth time.

Sharif's biggest challenge will be to wrestle back his support base from his main rival, Imran Khan, who despite being in jail remains popular following his ouster from the premiership in 2022.

Khan, too, is disqualified from the elections by virtue of his graft conviction in August, which he has appealed.

Sharif's return comes at a time when the nuclear-armed South Asian nation of 241 million people is experiencing the impact of a worst economic crisis, which was exacerbated during the 16-month rule of his younger brother, Shehbaz Sharif, who led a coalition government after Khan's removal.