Police were called to deal with incidents at schools in Hillingdon nearly 400 times in the last year.
Figures obtained by the Gazette under the Freedom of Information Act show police officers were called to schools in the borough 378 times last year, an increase of nine per cent on the previous year.
The offences officers were called to deal with included serious crimes such as sexual assaults and robberies, although police explained these were in the minority.
Inspector Andy Jones said: "Most calls are for low level offences such as thefts and fighting.
"We have been occasionally called to more serious incidents with drugs (and) serious assaults but such serious offences are few and far between.
"The figures don't alarm me, most of our schools don't generate major problems for us, you could say it is increasing because it's being made easier to report crimes."
Hillingdon Police have 10 Safer Schools officers who work in partnership with the schools to deal with incidents and ongoing issues, and many crimes are reported directly to them.
Inspector Jones explained on occasions calls could be reported by teachers, or by parents who judged a matter inappropriate to be dealt with by school discipline.
The number of crimes rose to 378 last year from 340 in 2007 and 315 in 2006.
"We do get a bit of gang culture so we do have to police that and work in partnership with schools to combat it. It is worth remembering that the school community is reflective of the community as a whole."
Julian Wooster deputy director, of children and families, for Hillingdon Council said: "Many of the incidents police are called out to at schools are not during school hours and do not directly relate to pupils.
"There is not a serious crime problem in schools in the borough and only 26 pupils were excluded for serious misbehaviour in Hillingdon schools last year, one of the lowest in London." * What do you think? Contact the Gazette on 01895451030