Mr Greg Dyke, who was appointed as director general of the BBC on Thursday, resigned from the British Labour Party yesterday and issued a strong defence of his fitness for the post.
He will meet the Tory party leader, Mr William Hague, who has criticised the appointment as an example of Labour cronyism, "as soon as possible" to ask him to judge him on his record in the post rather than his past political affiliations.
Mr Dyke pledged to create a BBC able to deliver "a broad range of outstanding programmes" which would capture the imaginations and affections of the public.
"Right across the world, the BBC has a reputation for honesty, fairness and independence. I can assure anybody here today that I am determined to safeguard this."
Downing Street again stressed that the government was not involved in Mr Dyke's appointment.
The Prime Minister's official spokesman said that they only learnt of the decision after the news was broken by the Tories.
"It is not a matter for the government. It is a matter for the BBC. The government played no role in it whatever," he said.
"I can see why the Conservatives and their supporters in the press wish to portray it in a way they do, but it bears no relation to the actual process."
Mr Dyke, who is currently chief executive of Pearson Television, was chosen from a list of 13 and a shortlist of five candidates, both internal and external, over a six-month process. BBC chairman of governors Sir Christopher Bland said it had been "fair and rigorous".
Controversy has surrounded Mr Dyke's candidacy since April, when it emerged that he had donated £55,000 to the Labour Party.
Yesterday, he said: "I have never found it difficult to separate my political activities from what I do as a professional."
Referring to Mr Hague's objections to his appointment, he said: "I recognise this is a perfectly valid journalistic and political issue to be raised.
"Certainly my immediate job is to reassure Mr Hague that I will be scrupulously fair at all times."
The Tory leader revealed Mr Dyke's appointment on Thursday night, and immediately attacked his fitness for the position.
However, Mr Dyke said he could not remember the last time he met or spoke to the Prime Minister, Mr Tony Blair, though he thought it was "probably last year".
Mr Dyke will start work at the BBC this autumn, and there will be a period of transition until outgoing director general Sir John Birt steps down in April 2000.
Sir John insisted he foresaw no problems during the takeover period between himself and Mr Dyke, whom he has known for more than 20 years since he first recruited him to LWT.
He also said he believed Mr Dyke was the right man to take over "a wonderful" job, adding: "You are at the very centre of national life. You are running the world's greatest cultural institution."
Mr Dyke said his priority would be to meet people and learn about the organisation. "I am a great believer in internal communications, walking the floor and talking to people," he said.
He warned sports lovers not to expect that his arrival would reverse the decline in the BBC's sports rights.
The growth of massively-funded pay TV had made that difficult he said. "There isn't a magic wand that says Dyke's here, so here comes the Premier League," he said.
Meanwhile, Manchester United said yesterday it would be reviewing Mr Dyke's position as a director on the club's plc board.
Figures for the last financial year showed he was paid £11,000 for his role as a non-executive director at the club, a position he has held since September 1997.
He attends the company's monthly board meetings as well as working on other occasional tasks and regularly going to matches.
Media group Pearson yesterday said Mr Dyke would step down from its board and leave his post as chief executive of Pearson Television in the autumn before taking up his new role.
He is also expected to leave his post as chairman of Channel 5, in which Pearson Television owns a 24 per cent stake.