Amnesty and Index are challenging the bans via judicial review. Amnesty's case will be heard in the High Court on 19 June. Survival is reluctant to get involved in an expensive legal battle. All three organisations are angry. Amnesty says its radio advert, highlighting the horrors of Rwanda, used a narration by John Hurt ("Listen - it is the silence in the councils of great nations where these difficult subjects are left unmentioned") and was to be broadcast on Virgin Radio and Classic FM. It insists it is not political but campaigns for prisoners of conscience everywhere. Its press officer, Brian Dooley, says: "All we're trying to do is to get the Government to abide by what it has already agreed within the UN Declaration of Human Rights."
Index on Censorship also made a radio advertisement recording the plight of a Haitian journalist who was tortured. The script was returned "unacceptable" by the authorities. Spokesman Philip Spender is cynical: "The boundaries of what is and isn't acceptable seem to be fluid depending on who you are."
The Survival ad featured Richard Gere and was broadcast on the music cable channel The Box and the MTV satellite offshoot VH-1. Gere urged viewers to help to stop the slaughter and exploitation of tribal people - until the advert was pulled in May. (It is still showing in cinemas, which are governed by different regulations.)
Survival's director-general, Stephen Corrie, is furious: "We are humanitarian, not political. They say we can't put pressure on governments to change policy, but there is nothing in our ad urging people to write to any government. Neither are we wholly or mainly political. Half of what we do is educational and field work.
"What about companies who seek to change government policies? British Airways lobbies on Heathrow, the AA on road building, and Hanson plc is the biggest commercial funder of this Government. Their adverts aren't turned down."
The Radio Authority defends its decision. "It's not the advert, it's the organisation whose objectives are wholly or mainly of a political nature,"retorts press officer Tracey Mullins. "We have to abide by the Act. We said the same to the anti-fur lobby. We're not singling anyone out."
Angela Salt, of the ITC, which has also banned Greenpeace adverts, says she is between a rock and a hard place: "The definition of political is very wide. When the Broadcasting Act was introduced, we lobbied the Government and said: 'Are you really sure this is what you want?'
"Now, what would be really interesting is if the governments Survival is criticising, who clearly have far more resources, tried to place an advertisement defending themselves. I wonder what the decision would be then?"