Listeners to Radio 4 in 1970 found their daily dose of news and current affairs much altered.

The controversial Broadcasting in the Seventies document had laid down plans for a new pattern of "generic radio".

The plan for Radio 4 was that it should become a "wholly speech network" - with an expansion of news and current affairs.

The spring schedules brought the first editions of PM and The World Tonight on 6 April - now two of the bedrocks of Radio 4.

The most radical changes in 1970 came in the "straight" radio news bulletins. For the most part, listeners were accustomed to hearing just one voice during a bulletin. That was the newsreader, delivering his script in traditional BBC style.

Only occasionally did they hear directly from the reporters and correspondents who'd helped gather the news. Even less often did they hear the voices and sounds that had been captured on tape "in the field".

That changed with the arrival of a new editor for radio news, Peter Woon. He wanted to start using the "on the spot" voices of reporters and correspondents for "all major stories". The declared aim was "to make better use of the BBC's unrivalled news services and to exploit radio's unique advantages over television and newspapers".

There was criticism in the press - especially over the technical quality of some of the material being broadcast. And it was acknowledged at Broadcasting House that "the difficult frontier between an acceptable technical quality and the desired journalistic authority and liveliness has sometimes been overstepped". But there was to be no turning back. The news executive who might have over-ruled Peter Woon was convinced.

"If the journalist reporting is really good, there is no substitute for hearing him say what he has to say", was his verdict. In his view, BBC radio news bulletins were now doing "more efficiently than before their job of telling people what is happening, and explaining it".

BBC TV's Nine O'Clock News began life on 14 September 1970.

It was broadcast a studio set that the Guardian described as "a sort of polystyrene padded cell".

The newsreader on that first evening, Robert Dougall, wasn't impressed either.

He had seen the lay-out for the first time only a few hours before. The desk was too small, he thought and the tiles looked "grey and lavatorial". Dougall took special objection to "a huge round thing" in the background - the new logo.

The bulletin itself was "rather jumpy", said Dougall, especially after a "weird electronic tinkle" at the start that he hadn't been warned about.

But audiences were high - and the Nine O'Clock News was to go on for thirty years.

The many changes included the appointment in 1975 of the first woman presenter, Angela Rippon. She threw off the traditional image of a BBC newsreader by taking to the dance-floor - on the Morecambe and Wise show. The result was immense publicity - but also mutterings about news becoming part of showbiz.

In 1981, the Nine O'Clock brought in its first journalist presenters - John Humphrys, later to join Radio 4's Today, and the current world affairs editor John Simpson.

Things went wrong from the start, says Simpson. Neither he nor Humphrys had ever read a bulletin before - and now they were doing it for real, without practice. It was rare at the start for the programme to go without a hitch, recalls Simpson.

The Nine O'Clock news report that perhaps had more repercussions than any other was the work of Michael Buerk - another journalist who was to become a regular presenter. It was Buerk's coverage of the Ethiopia famine in 1984 that inspired Bob Geldof to organise Live Aid.

The BBC Nine O'Clock News lasted until October 2000 - when it moved to a later slot, amid some controversy.

On 23 September 1974, the BBC started bringing news to the nation's televisions even when there was no bulletin on air. That was the date that marked the start of Ceefax - the system that enabled the viewers to "see facts" onscreen in the form of text.

It became possible thanks to BBC engineers who'd been looking at ways of providing subtitles for the deaf. They found that a normal television picture of 625 lines had "spare" lines at the top of the screen - that could be used to transmit words or numbers. The system that resulted was originally called Teledata.

The first time the public heard the new name was late in 1972, in advance of the first experimental transmissions. Ceefax was the world's first teletext service - though ITV's Oracle was to follow in less than a year.

The first Ceefax customers were able to choose from a range of 30 pages of information - news headlines, share prices, the weather and so on.

The problem in the early days was that customers had to buy a Ceefax decoder, that would set them back more than £300, or a completely new set, for about £700. As prices dropped, audiences grew. By 1985, the number of TV sets with access to teletext was more than two million.

As early as the mid-70s, one of the first Ceefax editors, Colin McIntyre, looked to the future - with uncanny accuracy. Ceefax was the start of a "video revolution", he said - when people would be able to "talk back" to computers, whether booking a holiday or ordering the weekly groceries.

The total number of Ceefax pages now stands in the region of 1,000 - ranging from flight-times to film reviews, from soap updates to surfing conditions.