A man will appear before magistrates next month for allegedly trying to organise a mass water fight via his mobile phone.

The prime minister said last week that the government would investigate whether social networking platforms should be shut down if they helped to "plot" crime in the wake of the riots.

The 20-year-old from Colchester was arrested on Friday after Essex police discovered the alleged plans circulating on the BlackBerry Messenger service and Facebook.

The unnamed man has been charged with "encouraging or assisting in the commission of an offence" under the 2007 Serious Crime Act, police said.

He was arrested with another 20-year-old man the day the water fight was allegedly due to take place, and has been bailed to appear before Colchester magistrates on 1 September. The second man was released without charge.

The BlackBerry Messenger service, a closed communications network, was the social network of choice for organising many raids on shops and businesses during last week's riots in England.

A police spokesman declined to disclose whether Essex police had been monitoring the service since the riots. "Essex police use appropriate measures for whatever the crime and wherever our investigations lead us," he said.

Speaking during last Thursday's parliamentary debate on the riots, David Cameron said he would investigate whether social-networking sites should be shut down if they helped to "plot" crime. The prime minister said he would "look at whether it would be right to stop people communicating via these websites and services when we know they are plotting violence, disorder and criminality".

He has received support from some Tory backbenchers, including Louise Mensch, who likened such a ban to closing a stretch of rail network after an accident.

In 2008 there was a spate of mass water fights in British towns and cities that were organised through social networks. Most remained peaceful.This month a water fight attended by thousands of young Iranians attracted the attention of Tehran's morality police and led to a series of arrests.