Seven-year-olds are bringing knives and other weapons into school, research has revealed.

The study conducted by the Centre for Social Justice (CSJ) warns there has been a "profound failure" by some schools to deal with violent or threatening behaviour.

The report, titled 'No Excuses: A Review of Educational Exclusion', found children as young as nine were regularly arriving at school dressed in local street gang colours.

The think tank, founded by work and pensions secretary Iain Duncan Smith, claims schoolchildren in some of Britain's poorest schools have been gripped by a "climate of fear" and wants to see a "radical reform on exclusion" to transform failing schools.

"The extent to which pupils in some of our schools are feeling unsafe and the impact that weapon-carrying street gang activity and conflict is having on their behaviour is staggering", the report states.

"During evidence to the CSJ, the head of a primary referral unit cited a number of examples of seven to 11-year-olds being sent to the pupil referral unit for having brought knives into their primary school. Often the children said they had brought the knives in because they were being bullied in school, to scare someone, or because they were being bullied by older children or, in one example, by someone's father, on their way home from school."

The think tank has recently called on the government to act quickly to combat the youth gang culture prevalent in today's society. Gavin Poole, executive director of the CJS, commented on David Cameron's address to parliament following the riots in August, and urged the government to prioritise the problem. "We all pay the price for our broken society and street gang culture", he said.

The results of the research are particularly relevant following the prime minister's education speech last Friday where he proposed to take away the benefits of parents whose children truanted.

The report added: "One witness to our review informed us that some pupils who truant may be doing so because they are getting robbed or bullied on the way home from school."

It also recommends police officers should be trained to work in schools with problem pupils heads and teachers should receive special training in conflict resolution.