An animal rights group has narrowly lost an attempt to open up paid political advertising in the UK.
Human rights judges in Strasbourg ruled in a 9-8 test case verdict that Government refusal to allow Animal Defenders International to screen a TV advert promoting animal rights was not a breach of ADI's freedom of expression.
The blanket ban in the UK is designed to prevent a political advertising free-for-all in which the richest have most access to promote their views - US-style aggressive political advertising.
Today's verdict rejected a complaint by the animal rights non-government organisation that denying it the possibility to advertise on TV or radio breached the European Human Rights Convention, which guarantees free speech.
The ruling by the smallest possible majority of the Strasbourg judges declared: "The court noted that both parties (ADI and the Government) maintained that they were protecting the democratic process.
"It found in particular that the reviews of the ban by both parliamentary and judicial bodies had been exacting and pertinent, taking into account the European Court's case law."
The judges said the ban only applied to advertising and ADI had access to "alternative media, both broadcast and non-broadcast".
The ruling also pointed out that there was a "lack of European consensus" on how to regulate paid political advertising in broadcasting - giving the UK Government "more room for manoeuvre when deciding on such matters as restricting public interest debate".
The verdict concluded: "Overall, the court found that the reasons given to justify the ban were convincing and that the ban did not therefore go too far in restricting the right to participate in public debate."
Culture Secretary Maria Miller said: "We welcome the fact the European Court has upheld the UK's blanket ban on political advertising.
"Political adverts are - and have always been - banned on British TV and radio. That ban has wide support and has helped sustain the balance of views which is at the heart of British broadcasting - and ensures the political views broadcast into our homes are not determined by those with the deepest pockets.
"This case was not about the particular views of this."
Ms Miller went on: "This case was not about the particular views of this organisation, but about the fact the Broadcast Advertising Clearance Centre considered that broadcasting this advert would breach the ban on political advertising in the UK."
The case was triggered by the BACC's refusal in 2005 to allow UK-based ADI, which campaigns against animal suffering, to run a TV advert juxtaposing images of a girl and then a chimpanzee in chains in an animal cage.
The BAAC said ADI's objectives were political in nature, and such a broadcast would breach the 2003 Communications Act.
The High Court and the House of Lords agreed and ADI went to the Human Rights Court.
Today's ruling said the Government and ADI had the same objective of "maintaining a free and pluralist debate on matters of public interest, and more generally, of contributing to the democratic process".
The human rights question was whether the ban went too far in restricting the right to participate in public debate.
The balance was between the NGO's right to impart information and ideas of general interest which the public was entitled to receive, and the authorities' wish to "protect the democratic debate and process from distortion by powerful financial groups with advantageous access to influential media".
The judges said they had taken account of the "complex" regulatory regime governing political broadcasting in the UK had been subjected to "exacting and pertinent" reviews and validated by both parliamentary and judicial bodies.
And at all stages, the compatibility of the law with the Human Rights Convention had been considered.
UK broadcast media was influential, with an immediate and powerful impact, and there was no evidence that this influence had been altered by the rise of the internet and social media to an extent which undermined the current broadcast restrictions.
Advertisers were well aware of the advantages of broadcast advertising, and continued to be prepared to pay "large sums" which went "far beyond" the reach of NGOs wishing to participate in the public debate.
The ruling pointed out that the ban was relaxed "in a controlled fashion" for political parties - the bodies most centrally part of the democratic process - by providing them with free party political, party election and referendum campaign broadcasts.
But, warned the judges: "Allowing a less restrictive prohibition could give rise to abuse and arbitrariness, such as wealthy bodies with agendas being fronted by social advocacy groups created for that precise purpose or creating a large number of similar interest groups, thereby accumulating advertising time."
ADI chief executive Jan Creamer said: "This is a profoundly sad day for democracy. It is unjust that companies can advertise without being challenged.
"This judgment has denied the right of ADI and other similar campaign and advocacy groups to refute advertising claims made by companies."
An ADI statement said the advert was tailored to comply with broadcasting rules but was banned because ADI was deemed to be a "political" group.
"At present, advertising laws effectively ban the broadcast of any advertisement on a matter of controversy. So, whilst primates and other animals can be used to sell products or services, it is not permitted to create awareness about the impacts of these actions on those animals.
"The injustice of the situation was highlighted at the time by the fact that soft drinks giant Pepsi were using a performing chimpanzee in a TV commercial," said the statement.
Tamsin Allen, a media partner at London law firm Bindmans LLP, which represented ADI, pointed out that the minority eight of the 17 human rights judges had accepted the case that the UK ban on all political advertising was an "inappropriate and unnecessary" restriction on free speech.
In their "dissenting judgment" the eight described the scale of the ban as "a harsher constriction of freedom than is necessary in a democratic society", adding: "Freedom of expression is based on the assumption that the speakers, not the Government, know best what they want to say and how to say it..."
Ms Allen said many small advocacy groups would be "extremely disappointed" that the majority of the judges had disagreed.
The Electoral Reform Society welcomed the verdict, saying that lifting the ban would have escalated an "arms race" on political spending.
Chief executive Katie Ghose said: This ruling should be welcome news to all democrats. Lifting the ban would have irrevocably changed the political landscape in Britain, and not for the better.
"The last Senate race in Pennsylvania cost more than our three main parties spent on the last General Election combined. And it didn't buy a higher quality of debate - just back-to-back attack ads."
She added: "The US experience shows the only people who would profit from TV attack ads are moneyed interest groups, TV networks and paid political consultants. The biggest loser would be democratic debate in Britain."