The issue of advertising on the BBC arouses strong feelings - as has been shown by the proposal to put ads on the BBC's international website.
Some argue licence fee payers are subsidising global users
Under the proposal, the international site would be renamed bbc.com and run as a commercial operation, with strong editorial and fair-trading safeguards.
But some MPs, BBC staff and commercial companies have been urging the BBC Trust to reject the plan.
The Trust replaced the BBC Governors at the start of the year and its approval is needed if the scheme is to go ahead.
Why the fuss?
Why indeed? Many licence fee payers would prefer the BBC to be funded by advertising if it meant they did not have to pay the licence-fee.
They say the BBC's TV and radio networks are already full of advertisements for its own programmes and services. They cannot see any problem if it charges other companies to advertise on its airwaves and website.
But many others say they cannot stand advertising. They do not want it cluttering up the BBC's airwaves and think it could damage the BBC's independence if advertisers tried to "buy" influence over its editorial decisions. These are two of the main concerns over the BBC website plans.
Doesn't the BBC share some of those fears?
Yes. In the policies section of its website, it says: "The BBC is not permitted to carry advertising or sponsorship on its public services.
"This keeps them independent of commercial interests and ensures they can be run instead to serve the general public interest.
"If the BBC sold airtime either wholly or partially, advertisers and other commercial pressures would dictate its programme and schedule priorities."
A key phrase here is "on its public services". This means those radio, TV and online services which are publicly funded - whether by the licence fee or the BBC World Service's grant from the government.
But the BBC already carries advertising on its commercial outlets.
These include Radio Times and other magazines; UKTV, the commercial TV service partly owned by BBC Worldwide; and BBC World, its global TV news channel.
Indeed, the BBC World website already carries advertising for companies like Barclays, HSBC and Shell.
Why does the BBC want to take advertising on the international website?
Overseas users of the BBC website currently make no contribution to its running costs. More than half the users of the news site are outside the UK.
They are more expensive to reach because their computers need overseas servers - and this cost will grow as more video is made available on the site.
Many opinion-formers now argue that international users should pay for the service and not be subsidised by the licence fee or the World Service grant-in-aid.
In any case, the current grant-in-aid will not stretch to provide all the new website infrastructure and services. Supporters of the advertising proposal say that without advertising, the BBC may have to bow out of the next wave of international news services.
What do those opposed to advertising say?
Forty-five MPs have signed an early day motion opposing the plan. Ten have written to newspapers as part of their campaign to persuade the BBC Trust to reject the proposal.
They said: "Senior foreign correspondents have warned that taking adverts will diminish the BBC's reputation overseas, and by extension, Britain's - particularly in the Arab world where suspicions of western corporate interests run high, the very region we should be seeking to grow our reputation."
A group of rival media owners has also urged the Trust to reject the plan, saying it could kill their own proposals for new digital services. They include major publishers and broadcasters such as News International, BSkyB, the Guardian, the Telegraph Group and Trinity Mirror.
Some BBC staff maintain that many people in the UK would be exposed to the advertising because the systems to prevent this are flawed.
They also fear that some overseas users will be driven away by the advertising, that inappropriate ads will appear next to news stories and that the website may slow down because of the need to insert ads across the world.
What does the BBC say?
It has not commented publicly. Privately, executives say they understand the complexity and sensitivity of the proposal and have been working for months to ensure the website would not be damaged either editorially or technically.
The proposal has been considered several times by the BBC's Journalism Board and its top executive board.
An "editorial guardian" would be appointed to ensure ads were not inappropriate and there was no commercial pressure on journalists.
Advertising could be excluded in countries where the issue is particularly sensitive (though they say that in some countries, commercial funding is regarded as a better guarantee of independence than government funding).
No pop-ups or deliberately intrusive advertising would be allowed. And they have taken steps to ensure the site would not be slowed down by inserting advertising.
What happens now?
The BBC Trust considered the proposal at its meeting on 21 February. An immediate decision was not be reached.
The BBC's other boards have taken more than one session to reach a decision, and the Trust asked executives for further information.