Police have warned there is "only so much they can do" to protect schoolchildren who take part in tuition fee demonstrations which turn violent.
The head of the Metropolitan Police's public order branch said schoolchildren have a right to protest but he also urged parents to talk to them about the "potential dangers".
Speaking ahead of a second day of national action, Commander Bob Broadhurst said: "Schoolchildren have as much right as anyone else to protest, but young people are more vulnerable and likely to be injured if violence breaks out.
"We would ask parents to talk to their children and make sure they're aware of the potential dangers, as there is only so much police officers can do once they are in a crowd of thousands."
On Wednesday 35 people were arrested and seven police officers injured after violence broke out during protests in central London.
Police were forced to defend their use of "kettling" tactics after thousands of protesters, including many school pupils, where held for about four hours in Whitehall. They also denied using police horses to charge the crowds.
Following the protest Britain's most senior police officer, Sir Paul Stephenson, warned of more disorder on the streets, saying "the game has changed".
Commander Broadhurst added: "The Met will always respect the right to protest peacefully, but I would urge all those considering taking to the streets of London again this week to think carefully about the consequences of engaging in violence and disorder."
Anyone wishing to contact the public order planning branch ahead of Monday's events can ring 020 7230 9833.