The teacher is convinced that this improvement is a result of the creativity that the computer game has inspired in his pupils.

The British government agrees. Last year Mr Rylands won the British Educational Communications and Technology Agency (Becta) award for the most innovative use of technology in the classroom.

Games likeTetris, for example, are also believed to improve mental spatial processing abilities. University of California, Los Angeles psychology professor Patricia Marks Greenfield cites video game playing as a major cause in the rise of non-verbal IQ in the United States in her book Mind and Media: The Effects Of Television, Video Games and Computers.

Still, parents often worry that their children spend too much time in front of a screen, be it the television, the computer or the video game console, and not enough time on their studies or outdoors playing with friends.

Besides concerns of graphical displays of violence and sexuality in game content and the strong language that tends to accompany them, parents fret over the intense immersion of children absorbed in gaming.

The visual electronic media activities of gaming, online chatting and watching TV frequently appear to parents as mindless preoccupations and are viewed as trivial and a waste of time, contributing nothing worthwhile to a child's intellectual or moral growth.

Earlier this year, a headmaster in a South London school that takes in pupils with behavioural problems who have been excluded from mainstream schools, claimed to have improved the academic results and behaviour of underperforming pupils by confiscating the game consoles, TVs and computers from their homes.

What will happen to our children who spend a disproportionate amount of their time on these pursuits? Will the effects be positive or negative? The answers to these questions are important because our culture today is soaked in digital media, and no child can escape its influence.

Video and computer game sales in the US alone hit US$7.3billion last year, putting it in the same league as movies, which raked in about US$9billion. Throw in sales of game consoles such as PlayStation 2, Xbox, GameCube and hand-held systems like Gameboy, Nintendo DS and PlayStationPortable, and the figure bloats to US$9.9billion.

In Hong Kong, video games were the main driver of growth in the toy and games industry, with export of video games growing by 30 per cent from January to October last year, and export of portable video games growing by 48 per cent in the same period.

In Britain and the US, more than 80 per cent of eight- to 19-year-olds have at least one game console at home. In the US, half of all children under six have used a computer and 30 per cent have played a video game.

Marc Prensky, founder and chief executive of game-based learning company Games2train, calls this generation of children who have been exposed to digital technology from birth 'digital natives'. Unlike the older 'digital immigrants', who have had to adapt to the new digital environment midway through their lives, digital natives are different in the way that they process information and in their language.

By the time an average student gets to college, he will have spent 5,000 hours reading but 10,000 hours playing video games and 20,000 hours watching TV, Mr Prensky says.

Today's children will spend their entire lives surrounded by and using computers, mobile phones, video games, digital music players such as the iPod, video cameras and all the other tools of the digital age.

'Digital natives are used to receiving information really fast. They like to parallel process and multitask. They prefer their graphics before their text rather than the other way round,' he explains. 'They prefer random access. They function best when networked. They thrive on instant gratification and instant rewards. They prefer games to 'serious' work.'

Just as Mr Rylands demonstrated in the Bristol primary school, games can be a boon to education because they are scripted in the same language as the children they aim to teach. Researchers Ellen Wartella and Nancy Jennings of the University of Texas, point out in their article Children and Computers - New Technology, Old Concerns that the current debates about the positive and negative effects of computers on children raise the same issues that have been raised with other new technologies in the past. For instance, positive educational benefits and the negative exposure to violent, sexual and age-inappropriate content were all deliberated when films were introduced in the early 1900s, radio in the 1920s and television in the 1940s.

Even books were viewed with suspicion when the printing press was invented. We fear the things that we do not understand.

An example of a video game that gets parents enraged is the highly popular but controversial Grand Theft Auto (GTA). In the game the player takes on the role of a street gangster, is able to steal cars, run over people, have sex with a prostitute then kill her - or not - and so on.

The latest release GTA: San Andreas caused a furore last year because of a software patch that could be downloaded which allows players to access and engage in explicit sex scenes. As a result of the uproar, the game's US rating changed from M for mature (over-17s only) to AO for adults only (over-18s). But GTA maker Rockstar North is in the process of relaunching an M version.

Whatever its rating, the fact is that GTA: San Andreas, with revenues of US$235million in the first week of its release, winds up in the hands of many children. This is of grave concern to parents and parental watchdog groups in the US such as MediaWise, Children Now and the National PTA, who are planning to get together to issue a set of ratings recommendations.

In spite of its objectionable content, Mr Prensky believes that GTA, with its explicit fantasy play, has a healthy dose of real-world education inherent in it, including helping players strategise based on results and consequences, making choices and examining options and sorting through conflicting values and feelings.

As the digital natives grow up, the generational divide will narrow. 'We force new technologies to prove that they are not the worst thing ever and eventually when we sort it out we relax a bit,' says Ben Sawyer, president of Digitalmill, a consulting firm that works on gaming projects.

'My guess is the next generation of parents won't be so apprehensive,' he says.