Chesterfield MP Toby Perkins now believes Labour leader Jeremy Corbyn could become Prime Minister - less than a year after saying he was 'not destined' for the role.
Mr Corbyn told the Sunday Mirror he can 'still be Prime Minister' - amid calls for a second General Election after Thursday's ballot returned a hung Parliament.
Last June, after Mr Corbyn won a second leadership contest to become leader of the party, Labour's Mr Perkins - who retained his seat with 26,266 votes - stood down as Shadow Armed Forces Minister.
In his resignation letter of June 27, 2016, he said: "As others have said, while most members hold you in great esteem, the majority who have contacted me also recognise that you are not destined to become Prime Minister and hope that you will stand down at the earliest opportunity to allow our party to approach the next General Election with confidence."
Today, when asked by the Derbyshire Times if he still agreed with those views, Mr Perkins said: "No.
"We outperformed my expectations and I think while we still have a long way to go, if we make the right steps, he could become Prime Minister.
"I and the rest of my colleagues will do whatever we can to give the country the strong opposition and prospective Government it deserves."
Labour won 30 seats in the General Election to take its total to 262 seats - but the Conservatives remain the largest party in Parliament with 318 seats.
Despite failing to secure a majority in the snap election, Conservative Prime Minister Theresa May has said she will not resign and has asked for support from Northern Ireland's Democratic Unionist Party to secure the eight seats needed to form a minority Government.