It's a school topic that seems to belong to an age far distant from home economics, 1066 and jumpers for goalposts. A school in Somerset has begun teaching 13- and 14-year-old pupils how to avoid defaming people on Twitter.

It is the latest way schools are adapting to technology and teaching about subjects such as online safety and cyberbullying.

The move at the private school in Taunton to teach pupils about libel risks on Twitter, Facebook and other social media follows the Lord McAlpine case. Earlier this year, the former Tory party treasurer announced he would sue a number of prominent Twitter users after being widely and inaccurately connected to allegations of child abuse in north Wales children's homes.

Taunton school said this had prompted teachers to extend teaching on the use of the internet and social media, which falls into the personal, social, health and economic, or PSHE, section of the national curriculum. The scheme, which may be extended to older pupils, began with lessons on basic internet safety, said Carol Manley, senior teacher at the school. She added: "We then realised that actually this was becoming quite a serious issue with things like parties on Facebook, the sorts of traps students can so easily fall into. From there we've really tried to keep abreast of social networking.

"Being the wrong side of 50, I wouldn't profess to be an expert on Facebook, Twitter or anything else, but I'm very aware of how much the children use it. We've become increasingly aware as a school that university admissions tutors are now accessing Facebook sites to check up on students."

Prompted by media coverage of the McAlpine case, the decision was made to teach pupils in year nine the basics of libel and defamation, not least how to avoid being chased for compensation.

Manley said:

"Of course, celebrities tweeting the wrong thing is in a different league to us, but it highlights how easily you can get something horribly wrong. It's a good opportunity for us to say to the children, look, even something that starts off as a joke or something silly can actually get you into a lot of trouble. They're also being taught to not even forward anything like that.

" We've been trying to make them accountable – if you wouldn't say something to a person's face, if you wouldn't say it in front of me or your parents, then you don't say it. I think that's the key bit that we try to get across to them."

As a private school, Taunton has the luxury of dedicated PSHE staff and has also been able to call in experts for one-off lectures, but it seems likely other schools could soon follow suit. A Law Society spokeswoman said it seemed sensible for pupils to be taught the basics of libel law. She said: "Social media may be one of the first areas where children are confronted by legal issues, as something as seemingly innocent as a retweet can sometimes lead to legal action."

At Taunton school, meanwhile, Manley has just taken delivery of a new educational DVD, the self-explanatory Think Before You Post. Pupils had to be aware that anyone can be defamed, Manley said.

"We see it in the context of celebrity status, but it could just as easily be the person round the corner who sues you," she added.

"Students need to know that whatever they say may just come back to bite them."