The Financial Times last night refused to run an advert criticising oil company Shell's activities in Nigeria that was paid for by human rights group Amnesty.
The full-page ad features a glass of champagne which has apparently had oil poured into it.
The FT said today that it had no problem editorially with the ad but pulled it for legal reasons.
The copy on the ad states: "While Shell toasts $9.8bn profits, the people of the Niger Delta are having to drink polluted water."
It goes on to make various statements about alleged pollution in the region and states: "If you've got shares in Shell, ask the board to explain themselves when they raise their glasses at today's AGM."
According to Amnesty, the Financial Times decided to pull the ad at 4.58pm last night in a move which they said was "extremely disappointing".
Tim Hancock, Amnesty International UK's campaigns director, said: "We gave them written reassurances that we would take full responsibility for the comments and opinions stated in the advertisement.
"Both The Metro and The Evening Standard had no problems with running the ad.
"The money to pay for the advertisements came entirely from more than 2,000 individuals online, who we'd asked to fund an ad campaign targeting Shell's AGM – and it really caught their imagination. And I am sure these supporters who have paid for the ad will be outraged."
A spokesman for the FT said: "Editorially the FT was more than willing to run the advertisement for Amnesty. Unfortunately, whilst Amnesty gave us written assurances that they would take full responsibility for the comments and opinions stated in the advertisement, it became apparent that Amnesty's lawyers had not had a proper opportunity to advise Amnesty on those opinions. As a result, from a legal perspective we were unable to rely on Amnesty's assurances."