In terms of the size of its audience, television has long since taken over from radio as the most significant from of broadcasting in Britain. Its independence from government interference is largely a matter of tacit agreement. There have been occasions when the government has successfully persuaded the BBC not to show something. But there have also been many occasions when the BBC has refused to bow to government pressure. Most recent cases have involved Northern Ireland. For a brief period starting in the late 1980s, the government broke with the convention of non-interference and banned the transmission of interviews with members of outlawed organizations such as the IRA on television. The BBC's response was to make a mockery of this law by showing such interviews on the screen with an actor's voice (with just the right accent) dubbed over the moving mouth of the interviewee!
There is no advertising on the BBC. But Independent Television (ITV), which started in 1954, gets its money from the advertisements it screens. It consist of a number of privately owned companies, each of which is responsible for programming in different parts of the country on the single channel given to it. In practice, these companies cannot afford to make all their own programmes, and so they generally share those they make. As a result, it is common for exactly the same programme to be showing on the ITV channel throughout the country.
When commercial television began, it was feared that advertisers would have too much control over programming and that the new channel would exhibit all the worst features of tabloid journalism. The Labour party, in opposition at the time of its introduction, was absolutely against it. So were a number of Conservative and Liberal politicians. Over the years, however, these fears have proved to be unfounded. Commercial television in Britain has not developed the habit of showing programmes sponsored by manufactures. There has recently been some relaxation of this policy, but advertisers have never had the influence over programming that they have had in the USA.
Most importantly for the structure of commercial television, ITV news programmes are not made by individual television companies. Independent Television News (ITN) is owned jointly by all of them. For this and other reasons, it has always been protected from commercial influence. There is no significant difference between the style and content of the news on ITV and that on the BBC.
The same fears about the quality of television programmes that were expressed when ITV started are now heard with regard to satellite and cable television. This time the fears may be more justified, as the companies that run satellite and cable television channels are in a similar commercial and legal position on those which own the big newspapers (and in some cases are actually the same companies). However, only about a third of households receive satellite and/or cable, and so far these channels have not significantly reduced the viewing figures for the main national channels.