Text messaging by mobile phone is 20 years old

British engineer Neil Papworth was just 22 when he sent the first ever SMS (Short Messaging Service) from his computer to a friend's Orbitel 901 mobile phone, on December 3, 1992.

The message read "Merry Christmas".

Speaking to the UK's Sky News over an internet video connection, Papworth said he didn't realise that text messaging would become such a big thing.

"Text messaging has gone on to even bigger and better things now," he said.

Papworth says he was working for the technology company Sema at the time, as part of the team developing a Short Message Service Centre (SMSC) for their client Vodafone UK.

More than 150 billion texts were sent in Britain alone in 2011, according to Britain's independent communications industries regulator, Ofcom.

Texting is now a more popular method of communication in the UK than making a phone call, Ofcom says.

The most frequent texters are 12-15 year olds, who send an average of 193 texts a week - almost four times as many as in the UK as a whole.

But, according to Ofcom, the first half of 2012 has seen a drop in the number of texts sent in the UK.

This is thought to be down to the increase in internet-based communications, such as Blackberry Messenger (BBM), iMessenger, Google Talk and MSN Messenger.

Many of these services are freely available on smartphones and tablets.