BLACON High School has been turned into a fortress to keep the pupils in and the yobs out.
Headteacher Barry Dykes pushed for the security measures which include children being locked on school grounds behind an eight-foot high fence topped with spikes.
An insider told The Chronicle the fence was erected after numerous incidents involving gangs of youths, including former pupils, who have gone onto school grounds during the day and who sometimes become aggressive.
Other features are four CCTV cameras and loudspeakers to communicate with trouble-makers at night-time who have previously set fire to vehicles and damaged sports facilities.
Wider benefits have been greater control over the students who can no longer come and go as they please although they have complained it 'feels like a prison'. Staff now have a more accurate record of who is in and out of school as well as keeping an eye on late-comers.
School governor Brendan Doyle said: 'My first instinct was it was a Fort Knox situation and it's a shame it's come to that but it's not been as negative as I thought and the benefits have been substantial.'
County councillor Doyle explained: 'You had kids that might have been excluded turning up and influencing behaviour. It was not a step that was taken lightly.'
He said schools were responsible for pupil safety and if anything went wrong they could be sued.
Chairman of governors Keith Butcher said: 'I think you will appreciate that security for all schools has become a very important issue after Dunblane, although I'm not suggesting there is a potential Dunblane.'
He added: 'We have a very large grassed area where the general public will just walk over that and this is the reason for the CCTV and, of course, we do get in schools people who are attracted to the IT equipment which is there and makes good thieving I suppose.'
Mr Butcher, who stressed the scheme had the full backing of the local education authority, added: 'I cannot emphasise enough that society has changed since we went to school and this is now necessary, it's not a case of producing a prison that you keep people in.'
There have been problems with vandalism and many glass windows have been replaced with shatter-proof plastic panels. Spikes now line a flat roof to help keep the yobs at bay.
At lunch-time the main gate is unlocked for pupils to come and go. Teachers patrol the inner and outer curtilages of the school to enforce good behaviour following complaints from residents and shopkeepers.
Students are locked out of the main building but are allowed in the 'youth club' where they have toilet facilities as well as a TV and video.
Caretaking staff and senior teachers have keys to the gate to ensure the emergency services can gain access.
One staff member said: 'It's getting like America but what do you do, wait until someone gets stabbed? Then people say you should have had security measures in place. The children don't like it, but it's for their benefit.'