Oliver Letwin, the shadow Chancellor, finally caved in to pressure and quit his job with NM Rothschild yesterday.
In a statement, he said he had quit the bank "to concentrate on winning the next election" and because his commitment to the Conservative Party "will always come first".
However, his decision caused confusion when it emerged that hours earlier he had given an interview implying that he intended to carry on with his Rothschild job.
Mr Letwin had told Bloomberg News he would not "be making any contribution to debates about taxation of the financial services industry" in future Government legislation.
On his appointment three weeks ago, Mr Letwin was criticised by Labour MPs for retaining his £100,000-plus post. At the time he said it helped him understand how the City was faring under Government policy.
He also said that he had declared his job in the register of MPs' interests.
As a director at NM Rothschild, Mr Letwinnormally started work in the City at about 7am before going to his office in the Commons.
He worked for the bank before becoming an MP in 1997 and continued after joining the Tory frontbench.
In his statement, Mr Letwin said: "It has become clear to me that I cannot continue with my work in the City. I have therefore decided to relinquish my [post] and to concentrate on winning the next election."
Ian McCartney, the Labour Party chairman, was scathing about the delay in Mr Letwin's response. "People will not trust the judgement of someone who tried to cling on to lucrative directorships."
Kevin Brennan, Labour MP for Cardiff West, who led the calls for Mr Letwin to give up his directorship, said it was "an ignominious and humiliating climbdown".