Television news channels that operate around the clock are cutting considered analysis and investigative journalism out of the picture, argues Alex Walker.

Digital satellite viewers can now pick from over two dozen 24-hour news channels from all over the world.

Along with Internet and mobile phone technology, 24-hour TV coverage offers us the chance to receive the news at almost any time.

But with this level of blanket coverage, has TV news disproved the old adage that you can never have too much of a good thing?

The theory behind constant television news coverage is that a viewer will be able to switch on at any time and pick up all the latest headlines in a matter of 20 minutes or less, much the same as picking up a newspaper and flicking through the main headlines.

This has a number of effects:

Firstly it means that only the most important stories (according to the producers' own news values) can be afforded valuable space on the constantly revolving merry-go-round of headlines.

The obvious result of this is that certain stories may be included at the expense of others.

In order to make this work, producers and editors will usually try to find stories likely to appeal to the largest (and usually the lowest) common denominator in order to keep the ever-crucial ratings up, disregarding stories that might appeal only to a minority interest group.

For instance, cricket fans may find the latest County Cup results pushed out of the hourly sports bulletin by football stories, or another more mainstream sport.

The danger of this prioritisation of popularity is that only the most dominant and popular ideological views will be represented, to the detriment of varied discussion and the interests of minority values.

Secondly, with the emphasis being placed on constantly revolving coverage where the main headlines of the day are given every 15 minutes or so, the stories must be compacted in order to fit enough of them in the required time.

Rather than providing the possibility for more detailed coverage - as you might expect from the luxury of 24 hours' worth of programming time - often the result is more succinct reports that may not have the time to cover anything more than the briefest details of a case, providing even less information than regular news bulletins on terrestrial channels.

Like flicking through the pages of a newspaper, you may well get a better overview of what is going on, but you will come away with very few details without reading the actual articles.

A combination of limited space in which to include stories and the pressure of making your news worth watching over any one of the dozens of competitors contributes to the increasingly ephemeral nature of news coverage.

For instance, in the interests of fulfilling the up-to-the-minute tag that usually accompanies 24-hour news, a story that may have been the lead headline one morning may have been pushed right back down the running order by lunchtime and might not even by appearing in the bulletins by the evening.

On the other hand, a nightly news programme would usually round up all the day's stories, no matter how early in the day they happened.

It could be argued that all news sources have a selected period of time in which to gather their stories (newspapers: the last day and night; magazines: the previous fortnight or month; websites: constantly updated) and that it would be counter-productive for news channels to loop stories to often as regular viewers would get bored of seeing the same thing over and over.

But it cannot be denied that a nightly round-up of a day's events lends itself much better to reflection and examination than a constant stream of ephemeral pieces of information.

In this way, 24-hour news definitely does stifle debate.

Reasoned debate comes from being well-informed on a matter.

By watching bulletins on a round-the-clock news channel, viewers will be informed about more, but not more informed about anything.

In other words, they will have a basic grasp of most stories, but without sufficient detail about any of them to really grasp the issue at hand. It is hard to see how they will be able to form valid opinions from such exposure.

As well as offering constantly available news headlines, another key aspect of 24-hour news is the ability to follow a story's development throughout a day, or longer.

Among the first instances where a story was followed almost non-stop by TV news crews were the space launches and moon landings of the 1960s.

Using new satellite technology (fittingly made available through the development of the space programme), American TV stations were able to provide viewers with constant updates and dramatic pictures of events.

A more recent example came during the Iraq War when most TV companies boosted their news coverage by 20 per cent or more to keep track of the event.

Some commentators compared war coverage to that of a sporting event, with detailed stats, close-up action shots and intermittent interviews with key players as well as "after-match-style analysis".

In these instances, it is hard to see where the border between entertainment and information in our news coverage lies.

US news stations have set an infamous precedent for their "rolling" coverage of news events, such as high-speed car chases which they track by helicopter or "stake-outs" of celebrities and criminals' homes.

The draw of this type of coverage is that, despite the fact that most of the time the footage is pretty tedious (car driving through the desert; outside of house with curtains twitching occasionally), people will keep watching until the crucial moment when the subject crashes and is “gappled” by the pursuing police or someone pops out to buy some milk, much in the same way we watch soap operas, every night waiting for the episode where Dirty Den's body is discovered under the patio or Sharon finds out her husband has been having an affair with the pub landlady.

Logically it would make more sense to just tune in for the evening news when you know you will see the key event(s) taking place, but the suspense and anticipation that accompanies a story developing in front of our eyes is often too engrossing to ignore.

But this further represses debate on the matter:

Print journalists would very rarely write up a story during the moment it was happening.

They would wait until the story had reached a satisfying climax and pen it in retrospect, allowing readers to benefit from a reflective and considered view of all events in perspective.

With rolling TV news this isn't possible.

There are occasions when instant reportage would be beneficial, such as election results or sporting events, but all too often TV news producers are inclined to dress up an event as "live" in the name of entertainment and excitement, leaving no time for reflective consideration from the reporter.

The blurred borders between information and entertainment are by no means exclusive to 24-hour news channels.

Most news broadcasters have been levied with charges of “dumbing down” their coverage with too much celebrity gossip and not enough commentary on politics and international affairs.

However, 24-hours news allows us 24-hour access to the celebrity soap opera that dominates so much of our lives, pushing "serious" news further out of already-packed schedules.

In many ways, 24-hour news is symptomatic of the development of news coverage in general.

As news agencies expand to global networks able to call upon correspondents in every country in the world, the natural outlet for a set-up that is providing large amounts of news is to have the ability to broadcast this constant input round the clock.

Channels are keen to show off just how global they really are in what has become one of the fastest growing businesses ever.

One of the ways they like to do this is with the clichéd satellite link-up, regardless of the feed.

Again, this can be useful at times, such as two-ways from the studio, but all too often the technique is used just because it can be, and because producers think that it looks good.

Modern news is all too keen to "go live" for no reason at all.

For example, on 14 July, BBC News went live to its North of England correspondent in Manchester for an update on the alleged Studabaker abduction case: "Tonight the focus of the story has moved from here to France…"

As well as being rather pointless, if reporters are constantly being required to appear in front of camera updating on stories throughout the day, it limits their time spent actually investigating stories to bring us red meat rather than chaff.

So not only is the information provided to viewers in diluted format, what is given probably isn't as reliable or insightful as it could if journalists were left alone by technology to carry out their true business of actually searching out information.

Twenty-four hour news is not like other specialist channels.

It is not a channel for people who like to watch the news in the way that round-the-clock DIY or sport enthusiasts might.

It lacks the reflective and reasoned perspective that evening news programmes have, and instead replaces the concept with rushed, sometimes poorly-produced news from reporters under immense pressure to deliver reports before the story becomes "stale".

The trend now seems to be that evening news bulletins are beginning to mimic 24-hour news channels.

This means all TV news could soon resemble the entertainment-focused stream of inconsequential updates that is our 24-hour news, leaving little room for real analysis and debate.

Instant news remains a prize, but at stake lies real and considered journalism.