Hosting his last media briefing as financial secretary yesterday, Tsang thanked the central ­government for its “trust and ­encouragement” over the years. He extended his gratitude to ­current and past chief executives.

“It has been a huge honour and privilege for me to have ­witnessed the historic moment of Hong Kong’s reunification with our motherland,” he said. “I am proud to see that the principles of ‘one country, two systems’... have been successfully implemented.”

“Whether I would run or not run is a serious and solemn matter ... I hope you would understand that I am not able to say any more than what I have said so far,” he said, promising to make a “responsible decision” in due time.

Tsang, who goes on leave from today, has to wait for Beijing to accept his resignation before announcing his widely expected bid.

While the career civil servant has faced his own share of criticism in the past, he has topped the popularity ratings for months, pipping other likely chief executive contenders such as Lam and executive councillor Regina Ip Lau Suk-yee.

Tsang has been at the helm of the city’s coffers for nine years, and has been known at times to differ from Leung in his approach towards economic policy.

Leung’s office issued a two-paragraph press release yesterday morning to announce Tsang’s resignation and his replacement by Secretary for Financial Services and the Treasury Chan Ka-keung. There was no word of thanks for Tsang’s years of public service.

Leung’s statement contrasted with that of his predecessor, ­Donald Tsang Yam-kuen, who issued a six-paragraph statement in September 2011 to express ­appreciation for then government No 2 Henry Tang Ying-yen, who resigned to run for the top job. Tang eventually lost to Leung.

John Tsang stepped down a day after the city marked a record turnout of 46 per cent in Election Committee polls, as 107,000 out of 230,000 eligible voters cast ballots on Sunday.

The 1,194-member committee that will pick the city’s next leader consists of 38 subsectors ranging from commerce and agriculture to culture and religion.

The pan-democrats made a significant advance this year ­compared with the last elections in 2011, grabbing a record 326, or more than a quarter, of all seats. They won landslides in sectors voted on by individuals, while pro-Beijing forces took those elected by corporate groups.

Although still a minority, the pan-democrats won enough seats to possibly sway the election result in March, because a chief executive candidate must secure at least 601 votes to win.

Mainland legal scholar Tian Feilong said he believed the ­central government would only want two pro-establishment ­candidates to join the race, to maintain control of the game. ­Beijing might persuade one potential candidate to withdraw, he said.

Some pan-democratic ­winners opposed Lam’s potential bid, expecting her to continue Leung’s high-handed style were she elected. But winners from the pro-establishment camp, such as Federation of Trade Unions members, held reservations about Tsang, saying he should not have quit his post without ­finishing the annual budget.

Former Liberal Party chairman James Tien Pei-chun, a winner in the commercial subsector, said he would lobby for Tsang in a personal capacity because “the business sector wants a CE who can bring harmony to society”.

Additional reporting by Gary Cheung and Emily Tsang