“Fly by night” language schools are causing overcrowding on public transport and unruly behaviour in the city’s parks.

That is the warning from one of the city’s pre-university colleges, following opposition councillors’ call for Oxford City Council to accredit the best language schools.

Green city councillor Nuala Young has called for a new forum for the pre-university, sixth-form colleges and summer schools which bring thousands of youngsters to the city each year.

It follows growing complaints about the behaviour of some students.

She said: “The fact is that you could say some schools are using the Oxford brand name without giving a good education.

“They are just really dropping the students on the streets and not taking them round places like the good language schools are.

“It is as bad for Oxford as it is for the students.

“I have talked to a lot of people who are hosting students, who tell me they are often not being treated properly.”

She added: “International young people need to get their money’s worth.”

And she said the problems caused by some students were getting worse, particularly in Headington Hill Park and South Park.

In September, police, the city council, bus companies and language college heads met to tackle the problems, including overcrowding on buses and noise and litter in the city’s parks.

The Oxford Safer Communities Partnership Language School Forum set out an action plan for the year to tackle crowding in public places, alcohol and litter in parks, and late-night noise.

It included the creation of guides to public transport written in Spanish, Italian and French, better communication between bus companies and language schools, and finding ways of identifying students and which language schools they attend.

But Abacus College principal Robert Swan warned that most problems were caused by “fly-by-night” colleges which often had no fixed address in the city.

Mr Swan said: “All the independent colleges already operate to the highest standards, and virtually all the problems come from colleges with no permanent premises, which do not come to meetings and do not have any local management other than a bunch of inexperienced students.”

He said the challenge was to encourage all institutions to get engaged in tackling complaints.

Mr Swan estimated that less than a third of the city’s 43 language schools had permanent premises, and these already worked closely with police and transport companies and gave their students ID cards.